Velour-like pile articles and pile surface structures and methods of making

ABSTRACT

A pile article having a support strand for attachment to multifilament yarn to form a velour-like pile having loosely entangled filaments in spaced apart monolithic pile rows, a helically wound package of oriented pile articles for shipping and storage, and a pile surface structure comprising pile articles arranged in spaced apart rows on a substrate to form a pile surface that may be flat or moldable, and a method for making a pile surface structure by embedding the pile articles into the backing substrate. The pile surface structures may be usefully employed in automobile mats, carpets and panels.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to a carpet mat and a moldable automotivecarpet.

2. Description of the Prior Art

Molded automotive carpets and mats are typically made using tuftedstructures where the pile yarn is tufted into a planar spunbonded sheet,the tufts secured to the sheet, and the sheet then attached to a sounddeadening backing to form a planar carpet. In the tufting process asignificant amount of costly pile yarn is on the side of the spunbondedsheet that attaches to the backing. With very short pile heights thepile yarn wastefully buried in the backing makes up a large percentageof the pile yarn used.

To shape the carpet it is placed between platens in a press. The platencontacting the backing is heated to permanently secure the carpet to thebacking. The carpet may also be molded and formed to the desired shapein the press. If it is desired to mold and shape the carpet the backingmust be deformable.

The pile yarn is typically a “singles” (versus two or more yarnsply-twisted) bulked continuous filament (“BCF”) yarn with relativelystraight filaments that is cut to give a velour appearance. Such acarpet requires a separate tufted sheet formation step and a laminatingstep to join it to a backing. During molding to a shape there issometimes a problem of separation of the rows of tufts during severedeformation required in some molds. This can be compensated by addingmore rows of tufts to the entire tufted sheet, but this results in ahigher cost carpet.

There is a need to simplify this process to reduce pile yarn waste andreduce costs without sacrificing quality.

Tuftstrings and tuftstring carpets are disclosed in U.S. Pat. No.5,547,732 (Edwards et al.), but the preferred embodiments there shownare intended for residential use on flat floors and are not adapted toreheating and forming. This patent does not teach use of a heavy sounddeadening backing nor variation of tuft spacing that accommodatesstretching during forming. It discloses an elongated pile article or“tuftstring” made using yarn comprising filaments attached to a supportstrand. In a preferred embodiment, the yarn is a ply-twisted bundle offilaments suitable for use in a cut pile residential carpet having a38.1 mm ({fraction (1/2)} inch) pile height. This preferred pile yarndoes not produce the velour look preferred for automotive carpets ormats. In one described embodiment of this patent the individual yarnsremain plied together when cut so the pile provides tuft definition atthe top surface of the carpet after assembly of the tuftstrings into acarpet. If the pile yarn along the length of the strand is examined theindividual pile yarns can be identified and there is little or noentanglement between individual pile yarns along the length of thestrand. All of the filaments in the pile yarns are also biased upwardsince they are bonded while bent over a ridge on a mandrel and thefilaments are preferably all entangled or ply twisted together into abundle. Such a preferred configuration of pile yarn is useful whenarranged in a final carpet structure, but it can be a problem whenstoring tuftstring in a wound package before assembly into a carpet, andwhen handling tuftstring at high speed during assembly into a carpet.

With the preferred tuftstring of the Edwards et al. patent, when tryingto get all the filaments to lie in a ribbon-like plane for winding, itis difficult to get the individual pile yarns aligned in the samedirection without some yarns crossing the strand either over the top orbottom of the strand. The individual yarns can act independently withsome yarns going one way and other yarns another. This is a particularproblem if the chosen strand does not have any significant torsionalstability. The upward configuration of all the filaments in the pileyarns also contributes to difficulties getting all the individual pileyarns bent into a flat ribbon for efficient winding. When guiding thepreferred tuftstrings for assembly into a carpet the above problemsassociated with individual pile yarns acting independently makes guidingdifficult, especially with a strand that has low torsional stability.Special guides are disclosed for handling tuftstrings described inEdwards et al. in the carpet-making process disclosed in relatedpublications WO96/06685 (Popper et al.) and WO97/06003 (Agreen et al.)(now U.S. Pat. No. 5,804,008. U.S. Pat. No. 5,804,008 is herebyincorporated herein by reference.

It is important that all pile yarn be oriented upright in the carpetassembly. If the tuftstring flips over due to torsional instability, andit is bonded to a backing in that orientation, the carpet assembly willbe rejected.

The Popper et al. publication also teaches a process for making moisturestable tuftstring carpets using ultrasonic energy for bonding thetuftstrings to a backing substrate. A preferred nylon carpetconstruction uses a nylon tuftstring having the nylon ply-twisted tuftsof the Edwards et al. patent attached to a nylon covered strand whichhas a fiberglass core. This tuftstring is bonded to a backing substratecomprising a fiberglass scrim placed between two layers of non-bonded,nonwoven nylon sheet to make a moisture stable carpet. Such a backing islightweight and flexible and is designed to be the final backing for aresidential carpet. The pile yarn lacks the desired look for anautomotive carpet and the backing is costly to use as an intermediatebacking for an automotive carpet construction that requires a layer ofheavy sound absorbing material for the backing. The glass scrim in thebacking and the glass in the strand would make the carpet inelastic sostretching and drawing would not be possible.

SUMMARY OF THE INVENTION

The present invention is directed toward a pile article (tuftstring)structure suitable for automotive pile surface structures (carpet, mator door panel) that is easy to guide for carpet forming and it is easyto form into a flat ribbon-like configuration suitable for winding intoa package. The tuftstring has a pile yarn comprising BCF singles yarn,that is not twisted, ply-twisted, or otherwise entangled to formindividual tufts, and that is cut to a pile height of less than 12.7 mm({fraction (1/2)} inch) and preferably less than 6.4 mm ({fraction(1/4)} inch). The strand can be a torsionally stable one with anuninterrupted outer surface, or one with a glass core with a wrappedstaple yarn sheath that has little torsional stability. The tuftstringso made surprisingly has a beneficial geometry for high speed handlingand flat winding. The filaments in the yarn are distributed along thelength of the strand in a monolithic loosely entangled array offilaments extending outward from the strand in two spaced apart pilerows, which provide some torsional stability to the tuftstringstructure. By torsional stability is meant that a 38.1 mm (1{fraction(1/2)} inch) length can be twisted one hundred eighty (180) degreesabout the axis of the strand and the pile yarn will still retain amonolithic structure without the filaments separating, and thetuftstring will return to near the original configuration unaided andwithout evidence that it has been twisted.

The distribution of the filaments about the strand has a surprisingconfiguration. Looking at the cross-section of the tuftstring there arefilaments along a lower side of each row that lie within ten (10)degrees to a plane defined at the base of the tuftstring. The remainingfilaments for each row are continuously distributed through an angularsector, having an origin in the base plane aligned with the width of thestrand, that extends from the lower side of the row to an upper sidethat falls between forth-five (45) and ninety (90) degrees from the baseand leaves a space between the two rows that is at least equal to thewidth of the strand. This space between the rows is important forinserting a guide member that contacts the strand without trappingfilaments between the guide member and the strand. The filaments at thelower side of the rows are in a position suitable for flat winding andthey are entangled with the remaining filaments which is believed tofacilitate flattening of the pile rows for flat winding. Theentanglement of the upper side filaments with the lower side filamentsalso is believed to restrain the filaments at the upper side of the rowsfrom coming together and closing the space over the strand that must bekept open for high speed guiding of the tuftstring. The filaments at theupper side of the rows are in a position suitable for forming a carpetpile surface when assembled with a backing substrate. The entanglementof the lower side filaments with the upper side filaments is believed tofacilitate reorienting the lower side filaments upward during carpetformation.

The arrangement of filaments is especially useful in an automotivecarpet mat when the strand used is comprised of a core of continuousglass filaments and at least one multifilament yarn wrapped at leastpartially around said core, although such a strand has low resistance totorsional twisting. The resulting tuftstring made with this strand istorsionally stable due to the arrangement of filaments in the pilestructure. The glass in the tuftstring provides a level of moisture andthermal stability for a mat that must lay flat under gravity and is notdraw molded.

The arrangement of filaments is especially useful in an automotivemolded carpet when the strand comprises a support strand having anuninterrupted outer surface (which may include a monofilament orextruded sheath/core). Such a strand should also be permanently drawablefree of fracture up to fifteen percent (15%) at a draw temperature ofone hundred fifty (150) degrees C. and a draw force of 8.9 N (2 pounds)or less at said draw temperature, to thereby limit the draw forcerequired for the tuftstring. With such a strand, the force required todraw the tuftstring is kept at a low level at a desired draw temperatureof one hundred thirty to one hundred eighty (130-180) degrees C. Thislimits distortion of the overall carpet structure during molding solateral separation or bunching of adjacent tuftstrings can be uniformlyconstrained by the backing substrate and the backing substrate is notdamaged.

The arrangement of filaments in the tuftstring is particularly usefulwhen making a pile surface structure preform, such as a preform for anautomotive mat or carpet, by guiding the tuftstring at high speed onto arotating drum covered with a backing substrate and embedding thetuftstring into the surface of the backing substrate. During suchoperation, the filaments forming the spaced monolithic pile rows provideresistance to torsional twisting of the tuftstring to aid handling andguiding, and maintain an open space between rows for a pressing tool toengage the strand without trapping pile row filaments between the strandand the tool or between the base of the tuftstring and the backingsubstrate. The surface of the backing substrate where the tuftstring isembedded may be tacky or may be caused to be tacky by the application ofheat, for instance.

A variety of backing substrates are useful with the tuftstrings formaking the automotive mat or moldable carpet preforms. The preformstypically are subsequently processed under heat and pressure betweenpress platens to form the finished mat or molded carpet. In oneembodiment a fabric layer is added to the backing before molding tostabilize the structure during and after molding. Any time after thetuftstrings are attached to the backing substrate, the bulkable pileyarn is treated with heat, or heat and moisture, to bulk the pile yarnand eliminate the spacing between pile rows so a uniform pile surface isformed in the finished product.

BRIEF DESCRIPTION OF THE FIGURES

The invention will be more fully understood from the following detaileddescription, taken in connection with the accompanying drawings, whichform a part of this application and in which:

FIG. 1 shows an automotive carpet known in the prior art;

FIGS. 2A, 2B, and 2C show a tuftstring; useful in an automotive carpetof the present invention; while FIG. 2D is an enlarged diagrammatic viewshowing the geometric relationship of various features of the tuftstringillustrated in FIG. 2A;

FIG. 3A shows an isometric view of one embodiment of a tuftstringautomotive carpet structure, and FIG. 3B shows a close up view of theattachment of the tuftstring to the backing;

FIG. 4 shows an isometric view of part of a molded automotive carpetstructure;

FIG. 5 shows an isometric view of a tuftstring forming device shownmaking one tuftstring;

FIG. 6 shows an elevation view of a tuftstring carpet forming system;

FIG. 7 shows an isometric view of a portion of the carpet formingsystem;

FIG. 8 shows an isometric view of another portion of the carpet formingsystem;

FIG. 9 shows an end view of a portion of a tuftstring carpet;

FIG. 10 shows an elevation view of another embodiment of a tuftstringforming device shown making four tuftstrings;

FIG. 11 shows an isometric view of an ultrasonic bonding module;

FIG. 12 is a view partially in section of a tuftstring forming mandrel;

FIG. 13 is an enlarged section view of the end of the mandrel takenalong line 13-13 of FIG. 12;

FIGS. 14A, 14B, and 14C are respective front, section, and side views ofan ultrasonic horn useful with the mandrel of FIG. 12;

FIG. 15A is a section view of a cutter for cutting yarn on the mandrel;

FIG. 15B is an enlarged detail section view of the groove in the cornersof the mandrel shown in FIG. 15A;

FIG. 15C is an enlarged view of the cutting edge of the blade shown inFIG. 15A;

FIG. 16 is an enlarged section view of two cutters engaged with themandrel shown in FIG. 15A;

FIGS. 17A and 17B show an elevation and a plan view, respectively, of aguide to direct multiple tuftstrings for bonding from the top side ofthe backing;

FIGS. 18A, 18B, 18C, 18D, and 18E are different views of an ultrasonichorn useful for bonding tuftstrings from the topside of a backingmaterial;

FIG. 19 is an isometric view of another tuftstring bonding device formaking twelve tuftstrings;

FIGS. 20A, 20B, and 20C are schematic section views of a mandrel to showdifferent arrangements for using a mandrel to make a variety of pileheights;

FIG. 21 is a schematic side view of the cylinder of FIG. 6 showing analternate way to retain the backing on the cylinder;

FIG. 22 is an alternate embodiment of the tuftstring carpet of FIG. 3;

FIG. 23 is a tuftstring carpet mat having a backing comprising a rubbersubstrate;

FIG. 24 is the mat of FIG. 23 with reinforcing strands in thecross-direction;

FIG. 25 is a tuftstring carpet mat having a backing comprising anadhesive-covered “Keldax” substrate;

FIG. 26 a tuftstring carpet mat having the tuftstrings attached to athin backing that is laminated to an adhesive-covered “Keldax”substrate;

FIG. 27 is a partial side view of a wound package of tuftstring;

FIG. 28 is plan view of a portion of a tuftstring carpet made withtuftstrings oriented at zero degrees and ninety degrees on a backing.

DETAILED DESCRIPTION

Throughout the following detailed description, similar referencenumerals refer to similar elements in all figures of the drawings.

FIG. 1 shows a prior art tufted carpet structure 31 useful for a mat orfor shaping in a mold for automotive use. The carpet structure 31comprises tuft yarn 33 tufted into a primary backing 35 of a spunbondedpolyester which is spray coated with an adhesive layer 37 of ethylenevinyl acetate hot melt resin sold under the trademark Elvax®, availablefrom E. I. du Pont de Nemours and Company, Wilmington, Del. (“DuPont”).It further comprises an extrusion coated layer 39 of a filledthermoplastic ethylene polymer sold under the trademark Keldax®, alsoavailable made by the E. I. du Pont de Nemours and Company. The layer 39functions as a carpet protective layer and sound barrier. The tuftingprocess requires a large creel of yarn during fabrication, and places asignificant amount of yarn 33 on the back of the primary backing 35 asthe tufting needles move and carry yarn from one row of tufts toanother. The use of a primary backing 35, the step of tufting, and thewaste of yarn on the back of the primary backing adds cost to the mat ormolded carpet. These costs may be eliminated or reduced by making a mator molded carpet using a tuftstring adapted for such purpose and using anew process for forming an automotive carpet.

FIG. 2A shows an elongated pile article, or tuftstring, 41 useful in theinvention. It comprises an elongated support strand 45 having athermoplastic outer surface 47 and having a width 69 and a height 613. Aplurality of thermoplastic bulkable continuous filaments, such asfilament 49, are bonded to one circumferential region 608 of the strandsurface 47 that extends along the length of the strand 45. The region608 defines a strand base 610. The filaments, such as filament 49, forman elongated loosely entangled array of filaments 614 extending outwardfrom the strand in two pile rows 616 and 618 spaced apart by space 617extending from the strand 45 to the cut ends 619. The rows are connectedtogether by continuous common filaments at a row base region 620. Thebase region of filaments 620 has a dense portion of filaments 622 bondedtogether to each other and secured to the surface 47 of the supportstrand at the strand base 610. The filaments in each row 616 and 618have a pile length 624, measured from the strand 45 to the cut ends 619,of between 2.5 mm (0.1 inches) and 12.7 mm (0.5 inches).

The circumferential region 608 along the length of the strand 45 definesan imaginary base plane 626 for the tuftstring. The pile filaments forrow 616 along a lower side 628 adjacent the base plane 626 define animaginary lower filament plane 630 for row 616. This filament plane 630is at an angle 632 to the base plane 626. The angle 632 has an origin634 in the base plane which is aligned with the width 69 of the strandat strand side 636. The angle 632 is preferably within plus or minus 10degrees of the base plane 626 and is most preferably about zero (0)degrees, or substantially aligned with the base plane. The filaments atthe opposed upper side 638 of row 616 defines an imaginary upperfilament plane 640 for row 616 that is at an angle 642 to the base plane626 with the origin at 634. The angle 642 is preferably 45-90 degrees,to thereby contain the filaments in the row 616 in an entangled arraythat keeps most filaments out of space 617 so strand 45 is freelyaccessible between rows 616 and 618.

The pile filaments for row 618 along a lower side 644 adjacent the baseplane 626 define an imaginary lower filament plane 646 for row 618.This-filament plane 646 is also at an angle 648 to the base plane 626.The angle 648 has an origin 650 in the base plane which is aligned withthe width 69 of the strand at strand side 652. The angle 648, like angle632, is preferably within plus or minus ten (+/−10) degrees of the baseplane 626 and is preferably the same as angle 632 and is most preferablyabout zero (0) degrees, or substantially aligned with the base plane.The filaments at the opposed upper side 654 of row 618 defines animaginary upper filament plane 656 for row 618 that is at an angle 658to the base plane 626 with the origin at 650. The angle 658, like angle642, is preferably the same as angle 642 at forty-five to ninety (45-90)degrees, to thereby contain the filaments in row 118 in an entangledarray that keeps most filaments out of space 119 so strand 47 is freelyaccessible between rows 616 and 618. However, the angles 632 and 642 forrow 616 do not necessarily have to be the same as angles 648 and 658respectively for row 618.

As best seen in FIG. 2B the tuftstring 41 has a guide groove 660adjacent side 636 of the strand 45 and guide groove 662 adjacent theopposed side 652 of the strand 45. The grooves 660 and 662 lie betweenthe strand 45 and the corresponding pile rows 616 and 618 respectivelythereby providing an elongated guide ridge 664 formed by the upperportion of the strand 45 which is accessible to a guide tool 666 thatmay be passed through space 617 between the spaced apart rows withouthaving to first move filaments from either row out of the way.Preferably, the guide ridge formed by the strand has a height of between0.13-0.76 mm (5-30 mils) measured from the base, and a width which isequal to or less than the distance between the pile rows at the baseregion. Preferably, the guide ridge formed by the strand has a width ofbetween 0.13-0.76 mm (5-30 mils).

FIG. 2C shows a tuftstring similar to that of FIG. 2A where the pilerows 616 and 618 have been forced upward to form a pile surface having avelour-like look as would happen when the cut pile tuftstring isassembled into a carpet, which will be discussed later. The filaments inthe rows are initially filaments of a plurality of yarns. Each yarn isbent over the elongated strand 45 and bonded to surface 47 atcircumferential region 608 along the strand. The bent yarn forms a pairof tufts, such as tufts 51 and 52 of pile yarn 43 that form part of eachrow of filaments 616 and 618. The tufts are indicated for purpose ofdiscussion by the shadow lines shown at the top of each tuft. Aplurality of yarns forming pairs of tufts are assembled along the lengthof the strand to form the rows 616 and 618. The individual filaments,such as filament 49, are free to blend and loosely entangle withfilaments of adjacent tufts where they come into contact along thelength of the strand. The tuft identity indicated by the shadow linesmay be visually absent within each row of filaments due to the blendingand entanglement since adjacent tufts are typically identical. Ifadjacent tuft yarns were different colors, they could be distinguishedafter bonding and cutting, but when they are the same in all respects,they cannot easily be identified from the top of the tuftstring afterbonding and cutting, or in a carpet made from assembled tuftstrings.

FIG. 3A shows an assembly of tuftstrings, such as tuftstring 41,attached to a backing substrate 34. The tuftstrings 41 and 41 a-c arespaced a selected distance apart, such as at 36, based on the desireddensity of tufts on the carpet, and are bonded along their length to thesurface 71 of backing 34. The support strand 45 is bonded on the insideof the “U” shaped yarns, and the bottom side of the tuftstring, that is,the bottom of the bonded “U” shaped yarns, is bonded to the surface 71of the backing. In the figure, the pile surface has a velour look due tothe blending of the filaments along the length of a single tuftstringand from one tuftstring to the other, so that individual tuftstrings andindividual tufts cannot be distinguished from the top pile side 40 ofthe carpet. In the embodiment shown the backing 34 comprises a laminateof an adhesive layer 42, a support layer 44, and a cover layer 46.

FIG. 3B shows an enlarged view of the base of the tuftstring and how itis partially embedded in the backing 34. The bottom surface or base 63of the tuftstring is below the top surface 71 of the backing 43 by adistance 71 a. This embedding is important to ensure the top surface ofthe backing substrate, in this case adhesive layer 42, engages a largeportion of the periphery of the tuftstring base 63 to securely attach itto the backing. The total thickness 54 of the backing substrate must belarge enough that significant compression can occur during attachment topermit embedding of the tuftstring.

In a scouting test of the tuftstring carpet integrity, the carpet isrestrained and a single tuftstring is grasped at one end and pulleduntil it separates from the backing. Three failure modes are typicallyobserved. A first mode is that the interface where the tuftstring joinsthe backing fails. A second mode is that the interface remains intactand the backing substrate fails or delaminates. A third mode is that theinterface remains intact and the dense region fails and the filaments inthe dense region separate from each other with some remaining with thebacking and some remaining with the tuftstring. A fourth mode is thatone of the other modes exists briefly and then the strand breaks. It hasbeen found that the first and second modes are preferred since theyusually result in a higher force to failure. The third mode usuallyresults in a low peel force failure. The fourth mode is rare.

To avoid the third mode of failure it has been found to be beneficial,for a given pile height, to place less yarn weight along the length ofthe tuftstring and place more tuftstrings per centimeter (inch) in thecarpet structure to get the desired pile weight in the finished carpet.For a given pile length, this means fewer filaments per centimeter(inch) in the dense portion of the base region. This facilitates thebonding of the pile yarn to the strand so the dense portion of filamentsat the base region does not easily pull apart, and the first or secondmodes of failure occur in the scouting test. When this is the case, thecarpet has been found to stand up well to normal carpet endurance andwear testing, such as Vetterman drum testing. Following this reasoning,it is preferred to place 2.4-3.9 tuftstrings per centimeter (6-10tuftstrings per inch) on the backing. This also results in a visuallyappealing carpet with uniform pile coverage and without rowiness.

In a preferred application the pile surface structure is used as acarpet in an automobile where it is molded to fit the single andcompound curvatures of the floorpan of a car. FIG. 4 shows a portion ofsuch a molded carpet 48 to illustrate some of the forming required. Thecarpet could be fabricated in a flat form or a pre-shaped form, heated,and placed in a mold to produce the three dimensional automotive carpet.To get from the two dimensional flat form to the three dimensionalcontoured form, the carpet must be drawn and in some cases compacted ormicrofolded as at compound curve 50.

To achieve the draw in the carpet structure 38 of FIG. 3A, the backing34 must be able to stretch in all directions and the tuftstrings, suchas 41, must be able to elongate. To achieve elongation of thetuftstrings, the strand 45 must be able to draw and permanently deformunder heat and pressure without failure. The temperature used must beless than the deformation temperature of the pile yarn of the carpet sothe pile is not damaged during molding.

A preferred drawable strand for a moldable carpet should not have toohigh a melt temperature compared to the backing, so the required moldingstretch at a low force can be achieved. The draw force for thetuftstring, which is primarily the draw force of the tuftstring strand,must be low enough to not damage the backing substrate. A high strandstretch force, when molding over a compound convex surface produces ahigh resultant force lateral to the tuftstring that must be resisted bythe backing to keep the tuftstrings from spreading apart. If the forceis too high and the backing is not strong enough at the deformationtemperature, the backing may thin out excessively and the tuftstringsmay spread apart non-uniformly. In the worst case, the backing may tearand a hole open up in the carpet that is visible from the pile side. Itis believed that a strand which will permanently draw fifteen percent(15%) at a temperature of one hundred fifty (150) degrees C. at a drawforce for the strand of less than ten (10) pounds will not generateexcessive draw forces when formed into a tuftstring, assembled into acarpet, and molded to make a three-dimensional contoured automotivetuftstring carpet.

The backing 34 in addition to being able to stretch in all directionswhen heated and pressed in the molding press, preferably provides asound absorbing or noise damping function in use as an automobilecarpet. A suitable such material is made by E. I. du Pont de Nemours andCompany under the trademark Keldax®. This material is a filledthermoplastic ethylene polymer that has an elongation to break of 450%and a density of 1.9 g/cc for a medium density product or 2.2 g/cc for ahigh density product. [Keldax®, 6868 is EVA (ethylene vinyl acetatecopolymer) with up to 70% Calcium Carbonate filler]. Keldax® polymermaterial can be joined with the tuftstrings as an extruded coating, aninjection molded surface or laminated as a pre-formed sheet or film. Asa film, the surface density may range from 1.5 to 4.4 kg/sq m (0.3 to0.9 lb/sq ft) when the high density product is used. In a preferredembodiment, the Keldax® has a density of at least 1 g/cc and a thicknessof at least 0.4 mm (15 mils).

To achieve good adhesion of the tuftstring, such as tuftstring 41 to thesupport layer 44, an adhesive layer 42 is required on the Keldax®polymer material. A preferred adhesive layer 42 for attaching a nylonpile yarn tuftstring to a Keldax® polymer material support layer is a0.08 mm (3 mil) thick polyethylene film modified with maleic anhydridemodified ethylene copolymer sold by E. I. du Pont de Nemours and Companyunder the trademark Bynel® CXA. (The preferred item is sold by DuPont asCXA 41E557.)

FIG. 5 shows a tuftstring forming module 55 and method for making asingle elongated pile article, or “tuftstring”, 41 by attaching pileyarn 43 to an elongated support strand 45. The strand 45 is guided alongthe edge, or ridge, 56 of a mandrel 58 and the yarn 43 is wrapped aroundthe mandrel and strand by rotating eccentric guide 60. One or multipleyarns may be wrapped at once; two are shown at 43 a and 43 b. The yarn43 is ultrasonically bonded to the strand 45 as it is pulled under anultrasonic horn 62 by movement of strand 45 and other carriers 64 and66. The wrapped yarn 43 is cut by a rotating blade 68 that intersects amandrel slot 70 so the strand with bonded yarn attached can be removedfrom mandrel 58 and guided to further processing steps as at 72. Theabove-described process and the tuftstring product produced is discussedfurther in U.S. Pat. No. 5,547,732 (Edwards et al.), which isincorporated herein by reference.

FIG. 6 shows an apparatus for carrying out further processing steps onthe tuftstring. The tuftstring forming module 55 of FIG. 5 is shown inthe left of FIG. 6 and the further processing steps are shown beginningat position 72. The single tuftstring 41 passes over a slotted drivenroll 74 where the tuftstring may have the pile height trimmed to adesired height of less than 12.7 mm ({fraction (1/2)} inch) by electricshears 76, and then proceeds to a forwarding and tensioning assembly 78.The tuftstring 41 proceeds to a carpet forming module 73 that comprisesa lathe type device 80 on which is mounted a large cylinder 82 forwinding the tuftstring onto a backing fabric in a spiral array. Mountedfor travel along the guideways of the lathe device 80 is a carriage 84that includes tensioning and guiding devices 86 and ultrasonic bondingdevices 88 for attaching the tuftstring to a backing 90 held on thecylinder 82. Flexible lines shown at 92 are for directing electricalpower, control signals, and compressed air to and from the movingcarriage 88.

In FIG. 6, after the tuftstring 41 has been traversed the length of thecylinder 82 (from left to right in FIG. 6 in the direction of arrow 94)and bonded along the length of the tuftstring to the backing 90, a pilesurface structure (tuftstring carpet assembly) 38 is produced on thecylinder. By slitting the carpet structure along the axis of thecylinder, the structure can be removed from the cylinder and laid flatlike a conventional carpet. The carpet may be subject to additionaltreatments, such as dyeing and bulking, after removal from the cylinder,or some treatments may be accomplished before removal from the cylinder.For instance, it is possible to place a housing around a portion of thecylinder surrounding a section of bonded carpet and supply a heatedfluid to the housing to bulk the carpet on-line.

The cylinder 82 of FIG. 6 is preferably covered with a thermalinsulative coating that slows the heat flow from the ultrasonicallyheated carpet elements to the cylinder. This is believed to make theultrasonic heating more efficient. One such coating that has been foundto work is a TFE-coated fiberglass made by the CHEMFAB company inMerrimack, N.H., designated Premium Series 350-6A. An acrylic adhesivemay be used to attach the coating to the metal cylinder. The TFE surfacekeeps the backing substrate from sticking to the coating. The thicknessof the coating may provide some resilience to the cylinder surface toreduce concentrations of force due to dimensional variations in theelements that may produce “hot spots” as the tuftstring is bonded to thebacking. If a thicker backing structure is used that provides some loaddistribution during bonding, or if the speed of the tuftstring under thehorn is greater than about 9.1 meters/min (10 yd/min) so significantheat transfer to the cylinder cannot occur in the time available, thensuch a coating may not be needed.

Other useful embodiments of the tuftstring and tuftstring carpet of theinvention are possible. FIG. 22 shows one such embodiment where thetuftstring is made with a monofilament yarn blended in with the normalcarpet pile yarn during production of the tuftstring as in FIG. 5. Themonofilament yarn has a larger dtex (denier) than the filaments of thecarpet yarn. The feed yarn 43 for the carpet pile could comprise two BCFpile yarns, comprising yarn 43 a, and two strands of clear nylon 6monofilament, comprising yarn 43 b (FIG. 5). When cut and assembled on abacking, the cut ends of monofilament yarn show up as large diameterfilaments, such as filaments 75, 77, 79, 81, and 83. These large cutfilaments are much stiffer than the surrounding pile yarn filaments,such as filament 49. The stiffer filaments can act as a brush when aperson's shoe is slid across the carpet as they are sitting in a carwhere the carpet is installed. This provides a useful new function of anefficient “doormat” where one can scrape off dirt from ones shoes whengetting into of out of the car, and yet while still preserving the lookof a fine automotive carpet. It would be expected that the stifferfilaments would also significantly extend the wear life of theautomotive carpet. The stiffer filaments may also tend to keep dirtparticles on the top surface of the carpet where they can be easilycleaned off, especially if the stiffer filaments are incorporated in anauto mat which can be easily removed from the car and shaken out.

The multifilament yarns 43 which are used as the pile, or tuft, yarnsmay be manufactured by various methods known in the art. These yarnscontain filaments (fibers) prepared from synthetic thermoplasticpolymers such as polyamides, polyesters, polyolefins, andacrylonitriles, and copolymers or blends thereof. Natural fibers such aswool may also be used. Preferably the polyamide (nylon) is selected fromthe group consisting of nylon 6,6 or nylon 6 homopolymer or copolymersthereof, sulfonated nylon 6,6 or nylon 6 copolymer containing unitsderived from an aromatic sulfonate or an alkali metal salt thereof,nylon 6,6 or nylon 6 copolymer containing units derived from2-methyl-pentamethylenediamine (MPMD) and isophthalic acid, nylon 6,6copolymer containing units derived from isophthalic acid andterephthalic acid, and nylon 6,6 copolymer containing units derived fromN,N′-dibutylhexamethylenediamine and dodecanedioic acid. One preferrednylon 6,6 copolymer contains about 1.0 to about 4.0 weight percent ofunits derived from the sodium salt of 5-sulfoisophthalic acid.

Preferably, the polyolefin is polypropylene homopolymer or copolymers orblends thereof such as a propylene/ethylene copolymer blend.

Preferably the polyester is selected from the group consisting ofpoly(ethylene terephthalate), poly(trimethylene terephthalate), andpoly(butylene terephthalate) and copolymers and blends thereof.Poly(trimethylene terephthalate) is especially preferred because it canbe used to make fibers having good carpet texture retention andwear-resistance properties.

These polymers are used to prepare polymer melts or solutions which areextruded through spinnerets to form filaments by techniques known in theart such as those described in the above-referenced applications. Thepolymer melt or solution may contain additives such as UV stabilizers,deodorants, flame retardants, delustering agents, antimicrobial agents,and the like.

In some instances, the multifilament yarns containing these filamentsare subsequently dyed to form colored tuft yarns. These yarns may bereferred to as pre-dyed yarns since they are colored prior tomanufacturing the carpet.

In other instances, a method known as solution-dyeing may be used tomake colored filaments which are then used to make the multifilamentcolored tuft yarns. Generally, a solution-dyeing method involvesincorporating pigments or dyes into the polymer melt or solution priorto extruding the blend through the spinneret. In a carpet context, thesemay also be referred to as pre-dyed yarns since the color is put in theyarn before the carpet is tufted or otherwise formed.

The pigment may be added in neat foam, as a mixture with the aboveadditives, or as a concentrate wherein the pigment is dispersed in apolymer matrix. For color concentrates, one or more pigments aredispersed in a polymer matrix which also contains such additives aslubricants and delustering agents (TiO2). The color concentrate is thenblended with the filament-forming polymer and the blend is spun intocolored filaments. For example, U.S. Pat. No. 5,108,684, the disclosureof which is hereby incorporated by reference, involves a process wherepigments are dispersed in a terpolymer of nylon 6/6,6/6,10 and pigmentedpellets of the terpolymer are formed. These pellets are then remelted or“let-down” in an equal or greater amount of nylon 6, mixed thoroughly toform a uniform dispersion, resolidified, and pelletized. The resultingcolor concentrate is then blended with a nylon copolymer containing anaromatic sulfonate or an alkali metal salt thereof. The nylon melt-blendis then spun to form stain-resistant, colored nylon filaments.

Typically, in a nylon filament manufacturing process the molten polymeris extruded through the spinneret into a quench chimney where chilledair is blown against the newly formed hot filaments. The filament'scross-sectional shape is dependent upon the design of the spinneret.Preferably, the filament has a trilobal cross-section with amodification ratio (MR) of about 1.0 to about 4.0. The cross-section ofthe filaments influences the luster (glow of the filaments fromreflected light), soil-hiding, bulk, and hand properties of the tuftyarns. The filament may contain voids extending through its axial core,as described in U.S. Pat. No. 3,745,061 or U.S. Pat. No. 5,230,957. Thepresence of voids in the filaments influences the luster and soil-hidingproperties of the tuft yarns.

The filaments are pulled through the quench zone by means of feed rollsand treated with a spin-draw finish from a finish applicator. Thefilaments are then passed over heated draw rolls. Subsequently, thefilaments may be crimped to make bulked continuous filament (BCF) yarns.These yarns have randomly spaced three-dimensional curvilinear crimp.Alternatively, the filaments may be crimped and cut into short lengthsto make staple fiber. Hot air jet-bulking methods, as described in U.S.Pat. No. 3,186,155 or U.S. Pat. No. 3,525,134, may be employed to crimpand bulk the yarn. Generally, for purposes of this invention, each yarnhas a bulk crimp elongation (BCE) of about 20% to 50%, and a dtex perfilament (denier per filament (dpf)) of about 17.6 to 27.5 (16 to 25).For entangled filament, loop-pile tuftstring carpets with good bulk, theBCE % may be toward the higher end of the above-mentioned BCE % range.For ply-twisted, cut-pile tuftstring carpets with good hand, the BCE %should be in a range of 27% to 49%, preferably 31% to 43%. For velour,cut-pile carpets with good resistance to felting, the BCE % may betoward the lower end of the above-mentioned BCE % range.

In the final carpet assembly, the tufts may have various forms such as,for example, loop-pile or cut-pile. Loop-pile tufts are characterized byhaving the yarn in the form of an uncut loop as described in U.S. Pat.No. 5,470,629, the disclosure of which is hereby incorporated byreference. The yarn in the present case, however, would be a straightyarn that has not been ply-twisted. Cut-pile tufts may be obtained bycutting the loops of the tuft yarns or preferably by the process shownin FIG. 5.

The final tuftstring carpet assembly may also be treated withstain-resist agents which provide resistance to staining of pile yarn byacid dyes. These stain-resist agents include, for example, sulfonatedphenol- or naphthol-formaldehyde condensate products and hydrolyzedvinyl aromatic maleic anhydride polymers as described in U.S. Pat. No.4,925,707. The tuftstring carpet assembly may also be treated withsoil-resist agents which provide resistance to soiling of the pile yarn.These soil-resist agents include, for example, fluorochemicalcompositions as described in U.S. Pat. No. 5,153,046.

Preferably, the tuft, or pile, yarn contains filaments made from apolymer that can be fusion bonded to the selected polymer of the strandby thermal fusion or solvent fusion or the like, whereby the originalpolymer used for the strand and tuft provide the means for joining thestrand and tuft, and the addition of a separate adhesive material is notrequired. However, the addition of a small quantity of adhesive materialto enhance fusion bonding may be desirable. The tuft polymer and thestrand polymer may be the same polymer or of the same polymer family.Preferably, the melt point of the strand polymer is less than the meltpoint of the pile yarn to minimize damage to the pile yarn filamentsduring bonding.

As described above referring to FIG. 3A, the inner surface of thebacking substrate may be coated with a polyethylene or polypropyleneadhesive film in order to improve the adhesion between the tuftstringsand the backing substrate. The film has a melting point greater than onehundred (100) degrees C. and less than the melting point of themultifilament nylon pile yarn. The film may be made by extruding a resinthrough a slot die onto a chilled roll. The resin solidifies to form afree-standing film which may be wound onto a core and stored for futureuse. Alternatively, the resin may be extruded directly onto the backingsubstrate to form the film. It is preferable that the thickness of thefilm on the backing substrate be in the range of about 0.08 mm to 0.13mm (3 mil to 5 mil).

The polyethylene or polypropylene composition comprising the resin maybe formed from a copolymer of ethylene or a copolymer of propylene withat least one of a C3-C10 hydrocarbon alpha-olefin, vinyl acetate, alkylacrylate, or alkyl methacrylate that has been grafted with a monomerselected from ethylenically unsaturated dicarboxylic acids andanhydrides thereof. Examples of the hydrocarbon alpha-olefins includebutene-1, hexene-1 and octene-1. Examples of the alkyl groups of themeth(acrylates) include methyl, ethyl, propyl and butyl. The graftingmonomer is at least one monomer selected from ethyleneically unsaturatedcarboxylic acids and ethylenically unsaturated carboxylic acidanhydrides. Examples of the acids and anhydrides are acrylic acid,methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonicacid, itaconic anhydride, methyl nadic anhydride, maleic anhydride, andsubstituted maleic anhydride. It is preferable that the grafted maleicanhydride polymer composition be used for purposes of this invention.Commercially available examples of such ethylene copolymers andpropylene copolymers include “Fusabond” adhesive resins available fromDuPont Canada, Inc. and are described in U.K. Patent Specification2,284,152. It is preferable that composition of ethylene copolymergrafted with maleic anhydride be used for purposes of this invention.

To form the adhesive resin these grafted polymer compositions may beused by themselves in concentrate form or they may be blended withnon-grafted polymers. Particularly, these grafted polymer compositionsmay be blended with non-grafted polymers such as medium densitypolyethylene (MDPE), low density polyethylene (LDPE), linear low densitypolyethylene (LLDPE), very low density polyethylene (VLDPE), andpolypropylene and blends thereof to modify such properties as themelting point, viscosity, and maleic anhydride content of the resin.Commercially available examples of such ethylene copolymer blends andpropylene copolymer blends include “Bynel” adhesive resins availablefrom DuPont (Wilmington, Del.). It is preferable that ethylene copolymerblends be used for purposes of this invention.

If the grafted polymer composition is used by itself in concentrate formas the adhesive resin, then the resin should have a melting pointgreater than about 100 C and in the range of about 100 to 130 C forpolyethylene-based compositions and about 130 to 170 C forpolypropylene-based compositions or ethylene/propylene-basedcompositions. In addition, the melt index of such a concentrate resinshould be in the range of about 0.5 to 30 dg/minute at one hundredninety (190) degrees C. and the maleic anhydride content of the resinshould be in the range of about 0.01 to 5.00% by weight of resin. Thesemelting point and melt index ranges provide a film having good stabilityin the carpet structure. The carpet may be subsequently bulked and thefinished carpet may be steam cleaned without backing delaminationproblems.

If the grafted polymer composition is blended with a non-grafted polymersuch as those described above, (MDPE), (LDPE), (LLDPE), (VLDPE), orpolypropylene, or blends thereof to form the resin, then the blendedresin should have a melting point greater than about 100 C and in therange of about one hundred (100) to one hundred thirty (130) degrees C.for polyethylene-based compositions and one hundred thirty (130) to onehundred seventy (170) degrees C. for polypropylene-based compositions orethylene/propylene-based compositions. In addition, the melt index ofsuch a blended resin should be in the range of about 0.5 to 30 dg/minuteat 190 C and the maleic anhydride content of the resin should be in therange of about 0.05 to 1.00% by weight of resin.

It is also believed that the adhesive resins may be formed fromunmodified polyethylene polymer or polyethylene polymer or copolymersand blends thereof provided that the resin has a melting point greaterthan 100 C and less than the melting point of the nylon pile yarn. Ifthe backing substrate is coated with a polyethylene film then thetuftstrings may be ultrasonically bonded to the backing substrate andthe tuftstring carpet may be bulked at a temperature of one hundredtwenty five (125) to one hundred eighty (180) degrees C. in a bulkingmethod as described below.

There are a variety of strand configurations that are useful in theinvention. One such strand is an extruded sheath/core structure wherethe core is a copolymer of polypropylene and the sheath is a copolymerof nylon. The core would comprise an 80/20 blend of polypropylene (Fina3868) and grafted polypropylene (POXT1015) and the sheath would comprisenylon 6 and nylon 6,6 available as Capron® 1590 from E. I. du Pont deNemours and Company. The weight ratio of polypropylene copolymer core tothe nylon copolymer sheath would be 50/50.

For a preferred pile yarn of nylon 6-6, the strand 45 may be amonofilament of a copolymer of nylon 6/12 polymer melt-blended with 15%Novalac resin from Schenectady Chemical as HJR12700, and Capron® 1590resin. The ratio of components is 60/20/20 by weight respectively. Thisprovides a strand that will bond with the pile yarn polymer that has alower melt point than the pile yarn polymer to thereby minimize pilefilament damage.

Another such strand is a sheath/core strand having a nylon staple yarnsheath of nylon 6,6 copolymer containing 30% by weight of units derivedfrom MPMD (2-methyl pentamethylene diamine) and a core of continuouspolymeric filaments that can be stretched or continuous glass filamentsfor carpet mats that do not require forming and stretching. The strandwrapped with nylon staple yarn of nylon 6,6 copolymer containing thirtypercent (30%) by weight of units derived from MPMD to be used as thesheath can be made by conventional means. For instance, a strand can bemade by wrapping a single staple sliver of 38.1 mm (1.5 inch) staplelength, 2.0 dtex/f (1.8 dpf) of the nylon yarn over a continuousmultifilament glass core of 1595 dtex (1450 denier). The total dtex(denier) of the strand may be about 2970 (2700) with a glass-to-nylonarea ratio of about 0.58. There would be good coverage of the glass andenough nylon polymer for good adhesion to the face yarn. Higher dtex(denier) strands with more staple fibers and a lower nylon/glass ratiowould also work. The machine used for making this wrapped strand is the“DREF 3 Friction Spinning Machine” manufactured by TextilmachinenfabrikDr. Ernst Fehrer AG of Linz, Austria. A similar machine is described inU.S. Pat. No. 4,779,410 (Fehrer).

The nylon staple yarn used for the strand sheath could also be a blendof staple filaments for special purposes. For instance, it may bedesirable to make a blend of 5-25% by weight lower melting binderfilaments (such as about 20% polypropylene filaments) with nylon6,6/MPMD staple yarn, or unmodified nylon 6,6 staple yarn to produce astaple blend that is wrapped around the glass core. When ultrasonicallybonded, the lower melting binder filaments may result in morecohesiveness for the strand in the axial direction and this may aid inresisting tuftstring damage during processing tensions, and resistingcarpet damage due to installation and handling tensions and wear in use.Other possible blended staple filaments may include filaments havingantistatic properties and such filaments could work with antistaticfilaments in the tufts to reduce static buildup in the finished carpet.

Strands having other wrapped structures can also be used. For example,nylon bulked continuous filament (BCF) yarns may be wrapped around thecontinuous filament core using a rubber covering machine manufactured byOMM America located in Natick, Mass. For instance, two BCF yarns may bewrapped in opposite directions of rotation around a fiberglass core toachieve coverage of the core and a balanced twist structure. Thiswrapped strand would function similar to the nylon staple yarn wrappedstrand, but the process would not have the same ease of blending inother polymer filaments for special functionalities.

The support strand may be comprised of a central core with a sheath. Thecore may be formed of a plurality of elongated filaments of fiberglassand filaments of staple yarn. The sheath may be a staple yarn wrappedabout the core. The nylon staple yarn sheath of the strand may comprisenylon 6,6 filaments made from nylon 6,6 copolymer containing about 30%by weight of units derived from MPMD (2-methyl pentamethylene diamine).The staple strands of the core would be the same material as the sheath.The nylon staple yarn comprising nylon 6,6 filaments made from nylon 6,6copolymer containing about 30% by weight of units derived from MPMD usedas the sheath can be made by conventional means. The strand can be madeby wrapping a staple sliver of 38.1 mm (1.5 inch) staple length, 2.0dtex/f (1.8 dpf) of nylon yarn over a continuous core of multifilamentglass of 1595 dtex (1450 denier) and a drafted staple strand which iscoextensive with the fiberglass multifilaments. The total dtex (denier)of the strand may be about 2970 (2700). The core is preferably about40-60% by weight of the strand. The staple filaments make up theremainder with preferably about 50-80% of the staple filaments being inthe sheath. The filaments of staple yarn and the filaments of fiberglassextend in the same direction. The wrapped staple sheath filaments engagewith the staple core filaments. This engagement is frictional beforebonding and additionally becomes a fusion engagement during ultrasonicbonding of the pile yarn to the strand. This is important to preventstripping-back of the wrapped staple yarn sheath (and attached pileyarn) along the core when the sheath surface (before bonding) or tufts(after bonding) meet resistance over rolls or guides in the handling ofthe strand and tuftstring in the carpet forming machines. It is believedthat most of the sheath filaments become bonded together and some ofthem are bonded to the tuft filaments during the ultrasonic process forattaching the tufts. This is an improvement over the strand andtuftstring where the wrapped staple does not adhere as well to the glassfibers in the core where there is no coextensive staple core covering. Amachine that can be used for making the wrapped strand is the “DREF 3Friction Spinning Machine” manufactured by Textilmachinenfabrik Dr.Ernst Fehrer AG of Linz, Austria.

As previously mentioned above, the nylon staple yarn could also be ablend of staple filaments for special purposes. Staple with a differentdtex (denier) per filament may also be used, although it may bedesirable to keep the dtex (denier) per filament of the staple less thanor equal to the dtex (denier) per filament of the pile yarn so there ispreferential melting of the staple strand filaments. In this vein, thestaple filaments used in the core may be different from the staple (orthe staple blend) filaments used in the sheath.

In using the staple wrapped strands mentioned above, there is sometimesa problem with uniformity of the staple sliver being used when slubs, orclumps of fibers, occur at random intervals along the length of thestrand. These clumps can create problems in handling the strand and inproper bonding of the strand using ultrasonics. It is possible todecrease this sensitivity to slubs by using two smaller dtex (denier)wrapped strands, as made in the discussion above, and plying themtogether to make a single, elongated, ply-twisted yarn supportstructure. For instance, each strand may comprise a core formed of aplurality of elongated continuous thermoplastic or thermally stablefilaments (fiberglass), and a sheath of staple yarn wrapped about thecore. The core of each strand [of about nine hundred ninety (990) dtex(900 denier) each if fiberglass is used] would be wrapped with a staplesheath (to provide a total dtex (denier) for each strand of about1650-2200 (1500-2000), and for a total dtex (denier) for the two-plysupport structure of 3300-4400 (3000-4000)). The individual strandswould be plied together at about 0.8-1.6 turns per centimeter (2-4 turnsper inch) in a conventional manner such as on a commercial ring spinningmachine made by Leesona Corp., Burlington, N.C. The plying also aids inpreventing stripping-back of the sheath along the core.

Referring once again to FIG. 6, it is important that the tuftstring becarefully guided onto the cylinder 82 and under the ultrasonic bondingdevice 88. FIG. 7 is a close-up view of a portion of FIG. 6 showing thetuftstring 45 as it is guided onto cylinder 82, covered with backing 90,by tensioning and guiding device 86. The ultrasonic bonding device 88consists of at least one ultrasonic horn 96 and ultrasonic driver 98attached to a flexible mount 100 that allows the horn and driver to movefreely in a radial direction relative to the cylinder. An arm 102 on themount 100 permits weights, such as weight 104, to be added to controlthe force the horn exerts on the tuftstring. The tensioning and guidingdevice consists of V-groove tensioning wheels 106 and 108, guide wheel110, guide groove 112, and other guides better seen in FIGS. 8 and 9.The V-groove in wheels 106 and 108 keeps the tuftstring upright andgrips it so a magnetic torque of the tensioning wheels can resist thepull of the tuftstring by the rotating cylinder, and thereby applytension. The magnetic tensioning wheels can be obtained from Textrol,Inc., Monroe, N.C. The tuftstring twists 90 degrees between tensioningwheel 108 and guide wheel 110 which also has a V-groove. The tensioningand guiding device 86 and bonding device 88 are attached to frame member114 that is attached to traveling carriage 84.

FIG. 8 is view 8-8 from FIG. 7 showing further details of how thetuftstring may be guided. It is important that the upstanding tufts ofthe adjacent tuftstring already on the cylinder do not get trapped underthe incoming tuftstring being bonded to the backing on the cylinder. Itis also important that the incoming tuftstring be positioned with thetufts upright and the strand directly under the ultrasonic horn. Toaccomplish these ends, in FIG. 8 a guide rod 116 is attached to framemember 114 and follows the contour of the cylinder close to the backingand presses sideways against the upstanding tufts of tuftstring 41 d tohold them away from the incoming tuftstring 41 e and ultrasonic horn 96.A guide plate 118 is attached to guide rod 116 and is placed close tothe backing 90 and at an angle to the bonded tuftstring 41 e. Anotherguide rod 120 is attached to frame member 114 and is placed close to theincoming tuftstring to keep the upstanding tufts upright and assist inguiding the incoming tuftstring 41 e under the horn 96. In a preferredembodiment, guide 120 would extend far enough beyond the last ultrasonichorn for bonding the tuftstring, which may be ultrasonic horn 96, tokeep the upstanding tufts upright until the bond for the tuftstring hadcooled sufficiently that it would not move or tilt over after beingreleased from the guide. If this incoming tuftstring 41 e, which hasouter tufts unsupported by tufts of an adjacent tuftstring, is releasedby the guide before cooling, it has been found that the outer tufts tendto lay over slightly during heating and as the bonded tuftstring coolsso that in the final carpet assembly this row of tufts produces avisible “streak” different than adjacent rows, even after shearing ofthe tufts, so the carpet has a defect called rowiness.

FIG. 9 shows another view 9-9 from FIG. 8 of guide rods 116 and 120 justin front of the horn 96. Guiding of tuftstrings 41 d and 41 e keeps thetufts from getting bent over and trapped under the horn 96 or betweenthe tuftstring 41 e and the backing 90 during bonding. To assist inalignment of the tuftstring under the horn, the leading edge 122 of thehorn 96 (FIG. 8) is radiused and this edge and the bottom edge arecontoured to receive the strand guide ridge 664 that comes in directcontact with the surface of the horn which acts as a guide tool. In thecase of an elliptical strand surface (after bonding with the yarn),these horn edges would be a concave radiused surface which can be seenin FIG. 9 at bottom surface 124. During high energy vibration of thehorn this contoured surface helps keep the strand from sliding out fromunder the horn. The pressure of the horn against the strand presses thetuftstring against the backing substrate to embed the tuftstring intothe surface of the backing. The backing is thick enough and deformableenough that the tuftstring is embedded below the backing surface0.13-0.63 mm (5-25 mils). In some cases, the backing surface is locallydeformed upwardly adjacent the tuftstring to accomplishment theembodiment.

FIG. 8 also shows another ultrasonic horn 126 that is useful whenassembling the tuftstring to the backing at high speeds, such as about9.1-22.9 m/min (10-25 YPM) tuftstring speed, and when high bondingreliability is required. Horn 126 is located close to horn 96 so thetuftstring 41 e is still hot from horn 96 when it is bonded by horn 126.In this way, the heating is partially cumulative and the total energyneeds for bonding can be shared by two horns. This permits operating athigh speeds which requires high bonding energy. At low speeds, secondhorn 126 is useful for “re-bonding” the tuftstring and improving bondreliability by bonding areas that may have been missed by horn 96. Itmay also be useful to use horn 96 just to accurately tack the tuftstringin place with low vibration and force, and use horn 126 to firmly attachthe tuftstring with high energy and force without the problem of thetuftstring moving around under the horn before bonding. This two horntechnique may also be useful for attaching pile yarns to the supportstrand, particularly at high speeds.

Bonding means other than ultrasonic bonding may be employed to attachthe yarn to the strand and to attach the tuftstring to the backing. Suchmeans may be solvent bonding or thermal bonding with, for instance, ahot bar; or some combination of solvent, conductive, and ultrasonicbonding. One means found to work well is to provide a tacky surface onthe backing, such as can be found when uncured rubber is used as abacking. Some pressure should be applied to the tuftstring strand toembedit in the backing. It is possible that the bonding occurs withoutthe separate addition of adhesive material to the tuftstring or backingwhen joining the tuftstring to the backing, however, it is preferred toinclude the addition of adhesive in the bonding area to achieve bondingbetween dissimilar thermoplastic polymers or to enhance ultrasonicbonding. Bonding using spaced apart areas aligned with the base surfaceof each tuftstring adhesive may also be achieved using methods describedin above-referenced U.S. Pat. No. 5,547,732.

In operation of the device of FIGS. 5 and 6, yarn from source 128 andstrand from roll 130 are fed to mandrel 58 where the strand travelsalong ridge 56 and to drive roll 132 in the forwarding and tensioningassembly 78. The yarn 52 is wrapped around the mandrel and strand andbonded to the strand by ultrasonic horn 62 to make tuftstring 51. Thetuftstring is threaded through the apparatus to cylinder 82. Backing 90is attached to cylinder 82 by tape 134 and is wrapped around thecylinder and cut to form a butt seam and taped to itself by tape 136 asshown in FIG. 8. The end of the tuftstring is threaded under the horn96, and horn 126 if used, and taped to the backing at the far left ofthe cylinder 82 where the carriage 84 is positioned for startup.Rotation of the cylinder 82 can now be started and the ultrasonic hornenergized to bond the tuftstring to the backing; the cylinder 82 acts asthe ultrasonic anvil. Carriage 84 is geared to the cylinder rotation soit traverses the desired pitch, say about 5.1 mm (0.2 inch), for onerevolution to advance the tuftstring along the cylinder and buildup aspiral array of tuftstring on the backing on the cylinder. When thecarriage has traversed all the way to the right of the cylinder, theprocess is stopped and the carpet wound on the cylinder is cut along thetape seam for the backing and removed from the cylinder. The process canthen be repeated. To control the speed and tension in the process, thespeed of cylinder 82 can be constant and tuftstring drive roll 132 canvary slightly in speed to keep the tension monitored by a tensiometer138 constant. The speed of a strand forwarding roll assembly 140 canalso vary slightly in speed to keep the tension monitored by anothertensiometer 142 constant.

Although the system shown in FIG. 6 for making the carpet winds only asingle tuftstring, it is within the scope of the invention to windmultiple tuftstrings and provide an ultrasonic horn that has multipleblades closely spaced for bonding multiple tuftstrings simultaneouslyusing a single ultrasonic energizer. A plurality of these multiple bladehorns could be arranged along a cylinder so numerous tuftstrings couldall be bonded at once and a complete carpet made rapidly with only a fewcomplete revolutions of the cylinder.

Although the systems shown in FIG. 6 shows a batch process for making acarpet assembly, it is within the scope of the invention to make acontinuous length of carpet by a warp process where there are enoughtuftstrings fed to the cylinder for an entire carpet width, and thecylinder serves as an anvil and a transport roll in the process. Thebacking would only make a partial wrap around the cylinder sufficient tobond the plurality of tuftstrings using multiple ultrasonic horns. Inthe FIG. 6 embodiment where the tufts are facing outward from thecylinder, one horn may have a plurality of blades for bonding aplurality of tuftstrings at once. The tuftstrings may be supplied inlinefrom a plurality of mandrels, or the tuftstrings may be made off-lineand supplied from wound packages, rolls, piddle cans or beams.

The pile yarn may be nylon 6,6 yarn which was solution-dyed, and nodrying process was necessary in making the assembly, as is required withlatex assembled tufted carpets. The carpet pile yarn was not subject tocomplete heating during assembly and was therefore not bulked. Thetuftstring carpet of this invention may be bulked after it has beenassembled. This bulking provides the carpet with greater covering power.The pile yarn is further bulked by heating the pile of the tuftstringcarpet. In one bulking operation, the tuftstring carpet is placed on atenter frame and passed through an oven, where the pile yarn is heatedwith a rapidly flowing stream of hot air and then cooled. In the case ofnylon 6,6 multifilament pile yarn, the air temperature may be in therange of about ninety to one hundred fifty (90-150) degrees C. whichraises the temperature of the tuft filaments throughout the pile yarn toat least ninety (90) degrees C. For purposes of this invention it ispreferred that the temperature be in the range of about one hundredtwenty five to one hundred eighty (125-180) degrees C. In a batchprocess as in FIG. 6, the carpet may be bulked by passing the pile yarnunder a cover supplied with hot air, or hot air and a water mist, or lowtemperature steam. As the drum rotates the cover would be traversedalong the drum to successively treat all of the carpet surface.

The invention is also useful for making carpet structures which do notutilize ultrasonic energy to attach the tuftstring to the backing. Forinstance, the backing may be a conventional uncured rubber backing whichis still tacky. The backing would have a release sheet on the drum sideand the side where the tuftstring is attached would be uncovered. Whenusing a tacky surface backing, the ultrasonic horn would not beenergized and would just act as a pressing means and guide.

During ultrasonic bonding of the yarn to the strands and duringultrasonic bonding of the tuftstrings to the backing substrate, it isbeneficial to direct a jet of cool air at the ultrasonic horns andultrasonic drivers to keep the temperature consistent during startup andcontinuous operation; heat buildup can cause variability in the bond.Some heatup of the ultrasonic driver does occur during continuousoperation which changes the efficiency of the unit. Changing the hornamplitude to maintain constant power corrects for this changingefficiency so stable bonds are produced. In order to start and stop theultrasonic bonding process and produce acceptable product, theultrasonic horn amplitude and horn pressure must be ramped up and downas the speed of the tuftstring ramps up and down. During steady staterunning, the tension on the yarn, support strand, and tuftstring must bemonitored and controlled, and the ultrasonic power monitored andcontrolled to be constant.

FIG. 10 shows an end view of a basic single mandrel tuftstring former150 using a four tuftstring mandrel 152. This is an alternate embodimentwhere four tuftstrings are made at a time instead of only one asdiscussed regarding FIG. 5. Major elements of the tuftstring former 150are the four-sided mandrel 152, a frame 156, a yarn wrapper 158, twoultrasonic bonding modules 160 and 162, a yarn feed module 164, a strandfeed module 166, a cutter arrangement 168, and a tuftstring drive module170. Yarn 43 is fed in through an idler feed roll 172 and driven feedroll 174 that are nipped together by fluid cylinder 176 acting aroundpivot 178 to grip the yarn 43 that may comprise one or several yarn endsfor each mandrel. Strands 45 a, 45 b, 45 c, and 45 d are fed in throughan idler feed roll 180 and driven feed roll 182 that are nipped togetherby fluid cylinder 184 acting around pivot 186 to grip the strands. Fourstrands are fed to the entrance end 188 of mandrel 152 where each strandis guided through a separate tube within a central hollow in the mandrelto keep the strands separated and prevent tangling. The mandrel isattached to frame 156 by bracket 190 on one side of the mandreldownstream from the cutter arrangement 168 that frees the wrapped yarnfrom the mandrel and forms four separate cut-pile tuftstrings. Thetuftstrings 41 f, 41 g, 41 h, and 41 i are fed through an idler exitroll 192 and driven exit roll 194 that are nipped together by fluidcylinder 196 acting around pivot 198 to grip the tuftstrings. Drivenroll 194 has grooves to hold the “U”-shaped tuftstrings and idler roll192 has ribs fitting into the grooves with the tuftstring therebetween.

FIG. 12 shows entrance end 188 of the mandrel 152 where the strandsenter and exit end 200 where the strands exit. FIG. 13 is an enlargedsection view of the exit end that shows a turning pulley for each strandthat guides the strand from a hollow passage 202 in the center of themandrel 152. Pulley 204 guides strand 45 a, pulley 206 guides strand 45b, pulley 208 guides strand 45 c, and pulley 210 guides strand 45 d. Thestrands are guided from the passage 202 to grooves on the corners of themandrel as discussed below.

The yarn is wrapped around the mandrel, and over the support strands inthe grooves on the corners of the mandrel, by wrapper 158 that comprisesa hollow spindle 212 with a yarn entrance end 214 and a yarn exit end216. The spindle is rotationally held by a bearing assembly 218 attachedto frame 156. The spindle is rotated by a motor 220 acting through apulley and belt arrangement 222. As the yarn 43 wraps around the mandrel152, the strands 45 a, 45 b, 45 c, and 45 d advance axially (downward)along the mandrel carrying the strands and yarn away from the wrapperand to the ultrasonic bonding modules 160 and 162.

FIG. 11 shows an isometric view of the bonding module 160 which is thesame as module 162, both of which are attached to frame 156 in analigned relationship on opposite sides of the mandrel 152 by brackets,such as brackets 224 and 226. The basic bonding module comprises anultrasonic horn 228 attached to a booster 230 and an ultrasonic driver232 attached to frame 234. Frame 234 is attached to four-bar linkageassembly 236 (two bars shown) which is attached to bracket 226. Fluidcylinder 238 is attached to frame 234 by clevis bracket 240 on the rodend 242 and to bracket 224 on the cylinder end. Motion of the fluidcylinder rod end 242 causes the ultrasonic driver, booster, and hornassembly to move in a direction toward and away from the mandrel 152while staying perpendicular to mandrel 152 to thereby squeeze the yarnbetween the horn and strand on the mandrel; the mandrel in this positionacts as an ultrasonic anvil. Squeezing together of the yarn and strandwhile ultrasonic energy is applied to the horn causes the yarn andstrand to rapidly heat, thereby causing the yarn filaments to fuse toeach other and to the strand where they are in contact. The yarn doesnot stick to the horn nor does the strand stick to the mandrel. Thefluid cylinder pressure determines the squeezing force exerted betweenthe mandrel and horn and the yarn and strand therebetween. This force isan important factor determining the amount of ultrasonic energy coupledto the yarn and strand. Other factors are the horn vibrational amplitudeand frequency.

FIGS. 14A-14C show the shape of the horn that permits one horn to bondtwo strands to the yarn at one time. In this way, only two horns areneeded to bond the four strands guided along one four-sided-mandrel. Thehorn 228 has two angled surfaces 244 and 246 that squeeze the yarn andstrand (neither shown) against the corners 248 and 250, respectively, ofthe mandrel 152. The surfaces are long enough so that if a largermandrel 152′ is used, the same horn 228 can still engage the yarn andstrand against the corners of the mandrel 152′. For a square mandrel asshown, the surfaces 244 and 246 are at 45 degrees to the side 252 of themandrel as shown at 254. For a hexagonal mandrel with one horn bondingon two adjacent corners, this angle would be 30 degrees. The shape ofthe surface 246 (and surface 244) is shown in the enlarged section viewin FIG. 14B to have an angled lead-in with a radius 256 to guide theyarn under the horn. To resist wear, the angled surfaces are preferablecoated with amorphous diamond available from Tetrabond, Inc., Divisionof Multiarc, Inc., Rockaway, N.J. Another coating that may work well isa chemical vapor deposited coating of titanium carbide and a furthercoating of titanium nitride. Another coating is a diamond coatingaccording to U.S. Pat. Reissue No. 29,285 (reissue of U.S. Pat. No.3,936,577) practiced by Surface Technologies, Inc. of Robinsville, N.J.The yarn would be traveling in the direction of arrow 258. In FIG. 14Cthe depth 260 of the horn 228 is small to minimize horn stress createdby the length of surfaces 244 and 246, and is large enough to clear allyarns expected to be used with the desired mandrel. The width 262 of thehorn 228 is about 12.7 mm (0.5 inches) and is a function of theultrasonic amplitude, frequency, and power of the driver.

Referring to FIG. 13, each horn, such as horn 228, is used to bond twosupport strands, such as strands 45 a and 45 d, to the yarn 43 wrappedthereon. This is preferably done by arranging the angled surfaces 264and 266 of horn 228 so they are essentially perpendicular to imaginaryplanes passing through the strands and bisecting the included angledefined by the yarn on the two sides of each strand. In this way, whenthe yarn is cut to form the cut pile tuftstring, the tufts on the sidesof the strand form the same angle at the base of the tufts where theyare bonded on. Imaginary plane 268 passes through strand 45 a andbisects included angle 270 between the ends 272 and 274 of yarn 43 bentover strand 45 a. Surface 266 is essentially perpendicular to plane 268as indicated at 276. Similarly, imaginary plane 278 passes throughstrand 45 d and bisects included angle 280 between the ends 282 and 284of yarn 43 bent over strand 45 d. Surface 264 is essentiallyperpendicular to plane 278 as indicated at 286. Notice that theimaginary planes 268 and 278 also intersect at the center or centroid ofthe cross-section of mandrel 152.

Referring to FIGS. 12 and 13, the yarn 43 is wrapped over four spacers288, 290, 292, and 294 on the sides of the mandrel 152. The spacers areheld in shallow slots in the sides of the mandrel. The purpose of thespacers is to increase the circumference of the mandrel seen by the yarnbefore the yarn is bonded. The spacers terminate at position 296adjacent the horns 228 and 228′. If the yarn is nylon 6-6, it has beenfound that the yarn contracts significantly upon cooling from theultrasonic heating, so as the yarn moves away from the horns, it passesbeyond the spacers at 296 and can contract to a smaller circumferencewithout binding on the mandrel.

After bonding, the yarn 43 must be cut to release it from the mandrel152. When cut precisely midway between the strands the cut end maydetermine the final tuft height of the yarn when the tuftstring isassembled into a carpet. When cut and assembled precisely, no furthertuft shearing is needed in the final carpet product, although for someproducts, shearing may still be preferred. The cutter arrangement 168 inFIG. 10 consists of four rotating circular blades each bearing against abed knife fixed to the mandrel. One such bed knife 298 is shown mountedin a slot 300 in mandrel 152 in FIG. 12. FIG. 15A shows section view15-15 from FIG. 10. Circular blade 302 is rotationally keyed to shaft304, is axially slideable along the shaft, and is urged by spring 306against bed knife 298. Circular clamps 308 and 310, one on each side ofthe blade, hold the yarn and support strand securely in the grooves inthe corner of the mandrel. The clamps are rotationally supported by, butare free of torque from shaft 304; and are axially slideable along theshaft. The clamps are free to rotate independently of the shaft drivenby movement of the strand. Springs 312 and 314 urge clamps 308 and 310,respectively, toward corners 316 and 318, respectively, of the mandrel152. The clamps securely hold the strand in the groove on the corners ofthe mandrel (and the yarn bonded to the strand) while the blades exert acutting force on the face yarn to cut it. The shaft 304 is rotatablysupported in housing 320 and is rotatably driven by motor 322 (partiallyshown). FIG. 15B shows an enlarged view of a groove 324 in the corner ofmandrel 152. The groove has a depth 326 and a width 328 about equal tothe major diameter of the strand. The bottom on depth 326 should bechrome plated to provide a smooth sliding surface for the strand. Depth326 may be between about 25% and 75% of the thickness, or minordiameter, of the strand to securely hold it, and still not interferewith surfaces 244 and 246 of the horn during bonding, and still supportthe yarn free of the mandrel for transport along the mandrel beforebonding. For a 0.71 mm (28 mil) diameter strand, a groove width of 0.66mm (26 mils) and depth of 0.20 mm (8 mil's) have been found to workwell.

As the bonded yarn and strands are propelled along mandrel 152, the yarnis pulled against the rotating blade 302 which cuts the yarn as it istrapped between the blade and bed knife. For efficient cutting of nylon6-6 yarn, it has been found that a blade material of C-ll grade,submicron, tungsten carbide coated at the periphery with amorphousdiamond (available from Tetrabond, Inc., Division of Multiarc, Inc. ofRockaway, N.J.) works well against a bed knife of D2 high speed toolsteel. Referring to FIG. 15C, the portions of the blade that arepreferably coated are portions 330, 332, and 334. The amorphous diamondcoating has a Vickers hardness of about 6000 units. Another coating thatmay work well is a chemical vapor deposited coating of two (2) micronsof titanium carbide and a further coating of two (2) microns of titaniumnitride. Such a coating would have a Vickers hardness of about 2600units. For improved life of the blade and bed knife surfaces, it hasbeen found useful to apply a cooling lubricant of water and a yarnfinish, such as an alkyl phosphate, to the side surface of the bladeusing a felt applicator pad kept moist by use of an intravenous-typedrip system or the like. Such a finish may be Zelex® NK anti-static yarnfinish available from E. I. du Pont de Nemours and Company. Theanti-static yarn finish is mixed with distilled water in a 0.5-2.0%volume ratio of finish in the mixture. The blade is believed to be mosteffective in cutting the yarn without undue wear by rotating the bladein the direction of yarn advance and at a peripheral speed slightlyabove (about 3-10%) the speed of the yarn passing under the blade. It isbelieved the low speed reduces the wear rate and the direction ofrotation minimizes any yarn tension increase during cutting. This causesa shearing action versus a sawing action where the peripheral speed ofthe blade is a lot faster (about 500-1000% greater) than the yarnadvance. However, acceptable cutting can occur when the blade is rotatedin the direction opposite the yarn advance and/or at a high speed so asawing action occurs. When using the shearing action, the cutting edgeangle 336 (FIGS. 7A and 7C) on the blade is preferably about 75 degrees(45 degrees for sawing), and the finish on the coated portions 330, 332,and 334 of the cutting edge is about 1-2 microinches rms. Although astationary bedknife and spring loaded blade have been described forurging the blade and bedknife together, it is possible to mount theblade 302 rigidly on shaft 304 and make the bedknife 298 moveable inmandrel 152 and spring loaded against the blade 302. It is also possibleto place the blade close to the bedknife without touching it, as will beexplained below referring to FIG. 19, and have the blade shaped asindicated by the dashed lines in FIG. 15C.

When cutting the yarns on the mandrel two blades can cut the yarn onopposite sides of the mandrel at the same longitudinal position (and atthe same time) since the cutters do not interfere with one another onopposite sides. The cuts can also be made by cutters spaced apartlongitudinally along the mandrel. This is possible since the clamps holdthe strand and attached yarn securely in the grooves on the corners ofthe mandrel as the cutters apply slight tension to the yarn duringcutting. The clamps counter the tendency for this tension to pull thestrand out of the groove. FIG. 16 shows two cutters with blades 338 and340 that may be at the same longitudinal position on opposite sides ofthe mandrel 152. In these cases, as the cuts are being made, rotatingclamps 342 and 344 hold the yarn cut by blade 338, and clamps 346 and348 hold the yarn for blade 340. The clamps are shown aligned with theblade, but they would also work if arranged on a shaft separate from theblade and placed adjacent the upstream side of the blade closer tointersection of the blade and bedknife where the yarn is cut.

It is desireable to wind several tuftstrings onto cylinder 82 at thesame time to speed up the production of the carpet. In this case, thereare a plurality of tuftstring guides for accurately guiding theplurality of tuftstrings onto the backing and under the ultrasonic hornsfor bonding. FIG. 17A shows an enlarged side view of a first tuftstringbonding horn 350 and a second horn 352 for bonding closely spaced,multiple tuftstrings; and a tuftstring bonding guide 354 for guidingclosely spaced, multiple tuftstrings into alignment with the first horn350. Each horn is mounted into a bonding module similar to that shown inFIG. 10 for bonding the yarn to the support strand on the mandrel. Eachhorn is forced in a radial direction, such as shown by arrow 356 forhorn 350, to squeeze the tuftstring against the backing substrate 90 andagainst the drum 82. The first horn is used to lightly tack thetuftstring to the backing while maintaining the alignment determined byguide 354, and horn 352 can apply more energy to the still heatedtuftstring to securely attach it to the backing. A large amount ofenergy can be rapidly put into bonding the tuftstring by the additiveeffect of two horns. The distance 273 between horns 350 and 352 shouldbe kept short to take advantage of this effect but this distance alsoprovides some time for the heat from the first horn to penetrate thesupport strand. At low speeds where a lot of energy does not need to beadded rapidly, only the first horn may be needed. This two-horntechnique may also be useful when bonding the face yarn to the strand onthe tuftstring forming mandrel. The horn 350, for instance, is shown inmore detail in FIGS. 18A-E. The horn in FIG. 18A has four forks 360,362, 364, and 366, each designed to fit between the tufts on a singletuftstring and contact the support strand at the base of the tufts. Thespacing 368 between forks is the same as the desired tuftstring spacingon the finished carpet. For different tuftstring spacings, differenthorns would be used with fork spacings. The height 370 of the forkscorresponds to the maximum length of the tufts on the tuftstrings forthe desired maximum tuft height in the finished carpet. The horn has alength 372 in FIG. 18B that is a function of the ultrasonic amplitude,frequency, and power of the driver. FIG. 18C shows a typical detail ofthe leading end 374 and trailing end 376 of fork 366 that shows a slightradius 378 to help guide the tuftstring smoothly under the horn. FIG.18D shows another possible shape of the fork where radius 378′ extendsthe length of the fork so the pressure is gradually applied as thetuftstring slides under the horn. Other shapes may also be beneficial,and first horn 350 may have a different shape than second horn 352. FIG.18E shows a typical detail of the profile of the tip 380 of fork 366that has a concave surface 382 that guides the support strand along thelength 372 of the fork to keep it from sliding to the side out fromunder the fork during bonding. This concave surface extends throughoutthe radius 378 and 378′ to aid in tracking the tuftstring strand underthe horn before the pressure and vibration of the horn acts on thetuftstring.

Referring to FIG. 17B, guide 354 has a plurality of slots, such as slot384, that has a narrow width 386 that forces the tufts on the tuftstringin toward one another and over the support strand. The slots for theplurality to tuftstrings converge to a spacing that equals the desiredspacing of the tuftstrings in the final carpet assembly. The slots guidethe tuftstrings at the proper spacing to the horn that has forks at thesame spacing and is closely spaced to the end 388 of the guide 354. Thetuftstrings approach the horn at an angle of about 15 degrees to thesurface of the drum so the concave surface in the horn helps in trackingthe tuftstring. At the forks, the tufts for the tuftstring guidedthereto separate so one row of tufts passes along one side of a fork andthe other row passes along the other side of the fork and the tip of thefork 380 is over the support strand and pressing against it. On one side390 of horn 350, the previously bonded tuftstrings must be pushed asideby plow 392 so individual tufts don't get trapped under the guidedtuftstring and bonded under the horn. On the opposite side 394 of horn350, there are usually no previously bonded tuftstrings present, so asupport finger 396 is attached to guide 354 to support the outer tuft onthat side of the horn. Finger 396 extends adjacent horn 352 and beyondto hold the tufts up until the bond cools. If the outer tuft is notsupported by finger 396, it has been found that the outer tufts tend tolay over slightly during heating and as the bonded tuftstring cools sothat in the final carpet assembly this row of tufts produces a visible“streak” different than adjacent rows, even after shearing of the tufts,so the carpet has a defect called rowiness.

After bonding is stopped on drum 82, the drum continues rotating a shortdistance and there is a plate 398 mounted under guide 354 that can beurged in the direction of arrow 400. The plate 398 is urged under theguided, but unbonded, tuftstrings and horns 350 and 352 so the guide,tuftstrings and horns can be lifted for tuftstring cutting, removal ofthe finished carpet, and threading of a fresh piece of backing onto thedrum. The guide, tuftstrings, and horn can be lowered and the platewithdrawn so the tuftstrings are in place against the fresh backing andunder the horn ready for bonding and restarting of the carpet makingprocess.

The tuftstring process is particularly amenable to using pre-dyed yarn(solution-dyed yarn) since the creel of yarn required can besignificantly smaller than with conventional carpet tufting operations.A small creel is an advantage when the creel must be changed for everycolor change for the carpet. When pre-dyed yarn is used in a tuftstringcarpet, the carpet structure must go through a separate bulking processsince other steps that provide bulking in conventional carpet systems,such as the carpet dyeing operation and latex drying operation, are notnecessary.

The single mandrel tuftstring former 150 in FIG. 10 or module 55 in FIG.5 require some special control considerations that can best be discussedreferring to FIG. 10. In order to start and stop the ultrasonic bondingprocess and produce acceptable product, the ultrasonic horn amplitudeand horn pressure must be ramped up and down, as the speed of thetuftstring ramps up and down. During steady state running, the tensionon the yarn, support strand, and tuftstring must be monitored andcontrolled, and the ultrasonic power monitored and controlled to beconstant. For example, distributed ultrasonic controller 409 (shown withtuftstring forming module 150 in FIG. 10) is connected to ultrasonicdrivers 232 and 232′ connected to horns 228 and 228′. Machine controller405 is connected to distributed controller 409 and to other elements, tobe discussed below, that are shown with coiled lines segments.

In addition to the elements already discussed referring to FIG. 10, thetuftstring forming module also includes four motors in the cutterarrangement 168; voltage-to-pressure regulators 452 and 454, cylinders238 and 238′, and ultrasonic drivers 232 and 232′ for bonding modules160 and 162, respectively; valves 456, 458, and 460 for cylinders 176,184, and 196, respectively; and tensiometer 462 for monitoring thetension on one of the completed tuftstrings, and tensiometer 464 formonitoring the tension on the corresponding strand, e.g., strand 45 a.

Motor 402 is responsible for pulling the strand through the mandrel 152,along the mandrel ridges, and pulling the tuftstring after the yarn isbonded on the strand and cut. When starting the tuftstring formingmodule, the speed of servo motor 402 is monitored by an attachedresolver, and the force exerted by cylinders 238 and 238′ on theultrasonic modules is ramped up and the horn amplitude exerted byultrasonic drivers 232 and 232′ is ramped up. Both the force andamplitude are ramped in a linear proportion to the ramping rate of thespeed of motor 402. There may be some slight delay to account forresponse delays in the horn and cylinder with the intent that the hornalways bonds all yarn to the strand without overbonding and severing anyyarn filaments. The force is controlled by machine controller 405controlling the individual signal to each voltage-to-pressure regulator,such as 452 and 454, on each bonding module. The amplitude is controlledby machine controller 405 controlling the signal to each ultrasonicdriver, such as 232 and 232′, on each bonding module. When the motor 402is up to a steady state speed, the machine controller changes fromamplitude control to power, or energy, control to maintain stablebonding conditions. The force is held constant, and the amplitude isvaried to maintain constant power to each ultrasonic driver and horn. Ithas been discovered that the ultrasonic driver efficiency changes as theunit heats up during continuous operation. Changing the amplitude tomaintain constant power corrects for this changing efficiency so stablebonds are produced. The horn itself has also been observed to heat up.Cooling air can be directed through conduits 455 and 457 to limit thetemperature rise experienced by the horn bonding surface; cooling airmay also be directed at the drivers.

When stopping the tuftstring, the machine controller changes fromconstant power control and the reverse procedure for starting isimplemented to ramp down the amplitude and force as motor speed 402ramps down. The baseline for the amplitude is that amplitude sampledjust before stopping is executed, since the amplitude is changing as theconstant power control is operated. Typical times to ramp the tuftstringspeed from about zero to fifteen (0-15) yard-per-minute (YPM) is aboutthree to five (3-5) seconds. It has been found in some cases, only theforce needs to be ramped at start and stop and the amplitude heldconstant, but the preferred operation is to ramp both force andamplitude.

During operation of the tuftstring forming module 55 or 150directly-coupled to the cylinder 82, the drive for the cylinder alsopulls the tuftstring so the tension of the tuftstring must be monitoredby a single tensiometer, such as tensiometer 462 for module 150 evenwhen an additional module may be used for more tuftstrings. The speed ofmotor 402 is then adjusted by machine controller 405 to keep thetuftstring tension constant. This prevents overtension and slack thatmay upset the process and break the tuftstring. Likewise, the strandtension must also be monitored by a single tensiometer 464 for eachtuftstring forming module 150, and the speed of motor 404 is adjusted bymachine controller 405 to keep the strand tension constant. Thetensiometers 462 and 464 are set up to measure the same strand linebefore and after the yarn is bonded to make a tuftstring.

The yarn feed roll motor 406 and wrapper motor 220 are controlled bymachine controller 405 so the tension is maintained constant in yarn 43being fed in and wrapped on mandrel 152. The controller sets the wrapspeed to achieve the number of strands per centimeter (inch) desiredalong the strand per operator instructions from the operator panel 407.The speed of motor 406 is set proportional to the speed of wrapper motor220 to achieve the desired tension based on trial and error. Atensiometer could be used on the yarn line between feed roll 174 andspindle entrance end 214, if desired, to aid in setting up the tensionand controlling it, but a fixed speed ratio has been found to work well.

Although the invention has been described in terms of making a cut pilecarpet, the tuftstring forming module 150 or 55 can be fitted with amandrel modules suitable for making loop pile tuftstrings. Such mandrelmodule would be based on the loop pile tuftstring apparatus and processdescribed in U.S. Pat. No. 5,470,629 incorporated herein by reference.In this case, more mandrels may be required since one mandrel makes onlyone loop pile tuftstring, although each loop pile tuftstring has tworows of loops so fewer tuftstrings would be required in the carpet toget the same coverage as a cut pile tuftstring. The loop pile tuftstringwould be forwarded to the carpet forming cylinder 82 as desired to forma loop pile tuftstring carpet. Guiding and bonding techniques similar tothose described for cut pile tuftstring would be used.

There are also other variations possible with the carpet assembly of theinvention using tufts attached to a strand to form tuftstrings that areattached to a backing. By providing multiple yarns in the yarn supply43, such as 43 a and 43 b, and winding them on the mandrel 152 as shownin FIG. 5, it is possible to distribute a variation in the yarn in acontrolled manner throughout the face of the carpet. Although variationsin the cross direction (XD) are possible in both the conventional andtuftstring carpets by making variations in the yarns from one strand tothe next or one tuftstring to the next in the XD, variations in the MDare not possible in the case of a conventional tufted carpet thatintroduces only a single continuous strand repeatedly in a straight orzigzag line in the machine direction (MD) of the carpet. It may bedesired, for instance, to sparsely introduce a particular effectthroughout the face of the carpet. Such an effect may be a colored yarn,an antistatic yarn, an antimicrobial yarn or one with other chemicalfeatures, an inexpensive yarn, a yarn with different texture, twistlevel, finish, dtex (denier), etc. For instance, the yarn for onetuftstring may comprise three yarns with only one of them being thedesired effect yarn, and the next adjacent two tuftstrings assembled tothe backing may not have the effect yarn at all. The effect then isdistributed sparsely in both the MD and XD of the carpet.

The use of a continuous strand in the carpet assembly offers thepossibility for additional variations in the carpet of the inventionwhich would not be possible with conventional tufted carpets withoutcostly additional steps after the carpet has been formed. For instance,antistatic filaments may be incorporated in some or all of thetuftstring support strands by placing them in the core of the strandduring strand formation. This would be combined with antistaticfilaments in some or all of the tuft yarns to provide enhancedantistatic automotive carpet performance for specialized vehicles andthe like where low static voltage buildup is important. The antistaticfilaments in all the strands may be grounded to the vehicle frame.

It may also be possible to transmit signals from one edge of the carpetto the other through the strands by incorporating a stretchable element,such as an optical fiber, in the strand in some or all of thetuftstrings. Other variations in effects and functionalities that areinherently possible with the tuftstring carpet assembly will be evidentto those skilled in the art using the teachings herein.

FIG. 19 shows an alternate process for making tuftstring useful in anautomotive tuftstring carpet. On this mandrel, strands are additionallyconducted in guide grooves along the flat surfaces of the mandrel andbonded to the wrapped pile yarn by horns located there. FIG. 19 shows amandrel for making 12 tuftstrings, such as those schematically indicatedat 466, 468, and 470. The mandrel 472 has guide grooves on ridgespositioned at the corners, such as corners 474 and 476, for guiding foursupport strands, and guide grooves on the side surfaces between theridges, such as surfaces 478 and 480, for guiding two additional supportstrands on each surface for a total of eight more strands. On surface478, there are shown two strands, 482 and 484, each in a guide groove(not shown). Yarn 486 is wrapped over all the strands by wrapper 488 toform loops of yarn around the mandrel and support strands. Cornerbonding ultrasonic horns 490 and 492 bond the yarn 486 to the cornerstrands as described earlier referring to FIGS. 13 and 14A-14C.Alternatively, four separate horns could be used with one on each cornerfor individual control of bonding parameters for each tuftstring.Bonding of the corners is important for transporting the wrapped yarnloops before bonding on the side surfaces. Ultrasonic horns 494, 496,498, and 500 bond the wrapped yarn to strands on the side surfaces usingthe mandrel as an ultrasonic anvil. There may be replaceable inserts(not shown) used for the groove portion directly under the horns so worngroove areas could be simply replaced without replacing the entiremandrel. Spacers (not shown) would be provided to accommodate yarnshrinkage during bonding as described earlier referring to FIGS. 12 and13.

After all strands are bonded to the yarn 486, the yarn 486 is cutbetween the strands by 12 cutting blades located at the same positionalong the length of the mandrel 472, such as blades 502, 504, and 506 onone shaft 508 driven by motor 510. Each blade intersects a slot in themandrel (not shown) with about a 0.25 mm (10 mil) clearance on eachside. The blades may be made from a variety of materials as previouslydiscussed, which includes a ceramic, such as ittria stabilized zirconiaavailable from Ceramco, Inc., Center Conway, N.H. The blade entering theslot may be from 0.8 to 1.6 mm (0.03 to 0.06 inches) thick with a sharpend at the perimeter having an included angle of from 20 to 45 degrees.When the blades are all cutting at the same position along the mandrel,the strands do not have to be held in the grooves on the corners andside surfaces. The grooves for the strand and attached yarn 486 holdsall the strands from lateral motion during cutting. After cutting it isnot critical that the strands remain in their grooves. The position ofthe blades relative to the strands determines the pile height of thetuftstring. The tuftstrings, such as tuftstrings 466, 468, and 470, thatare separated at cutting are individually conducted away from themandrel for winding onto reels or spools (not shown).

The mandrel 472 may be provided with a variety of grooves for makingtuftstrings having a variety of different pile heights. FIGS. 20A, 20B,and 20C show end views of two corners and one side of mandrel 472 formaking a variety of pile heights. FIG. 20A shows three tuftstrings 512,514, and 516 that would provide a pile height of 9.7 mm (0.38 inch) fora mandrel 38.1 mm (1.5 inches) on a side. Strands 511, 513, and 515 areguided by grooves 517, 519, and 521 respectively. The mandrel hasrelieved channels, such as channels 523 and 525 extending between guidegrooves on the mandrel in the vicinity of the side surface bonders, suchas ultrasonic horn 494. These channels prevent bonding of one loop ofpile yarn to an adjacent loop of pile yarn between support strands alongthe sides of the mandrel. Cutter blades 518, 520, 522, and 524 would beprovided in slots 526, 528, 530, and 532 respectively for cutting thetuftstrings from the mandrel. FIG. 20B shows the same mandrel with fourtuftstrings 534, 536, 538, and 540 having a pile height of 6.4 mm (0.25inches). FIG. 20C shows the same mandrel with five tuftstrings 542, 544,546, 548, and 550 having a pile height of 4.8 mm (0.19 inches). In thisway one mandrel can be provided with all the necessary grooves andcutter slots to make a variety of pile height products. The number ofstrands and cutter blades would be provided as required for a particularpile height.

Referring to FIG. 6, the tuftstring module 55 can run essentiallycontinuously, while the carpet forming module 73 essentially runs as adiscontinuous process making one carpet at a time after which it must bestopped, the carpet removed, and the system set up for the next carpetto be made. For efficiency in manufacturing, it may be desireable toseparate the continuous function from the discontinuous function. Thiscan be done by winding up the tuftstrings on packages at position 72that can be automatically changed while the tuftstring module continuesmaking tuftstring. The wound packages of tuftstring can be fed into thecarpet making module 73 and easily started and stopped as the carpetsare made and completed.

EXAMPLES Example 1 Moldable Automotive Construction Based onThermoplastic Backing and Strand

A carpet structure was fabricated in the following manner: first, atuftstring was fabricated on a triangular mandrel similar to that shownin FIGS. 5 and 6. The tuftstring was formed at 1.8 meters (2 yards) perminute by wrapping two strands of 1546 dtex total (1405 total denier),producer colored, bulked continuous multifilament nylon 6,6 yarn,produced commercially by the E. I. du Pont de Nemours and Company,around the triangular mandrel. A monofilament sheath/core strand wasused for the tuftstring strand. The ultrasonic power used to bond thepile yarn to the strand was 30 watts and the ultrasonic tool loading ona 19.1 mm ({fraction (3/4)} inch) long tool was approximately 10,500kg/sq m (15 psi). There were 10.2 (26) single wraps of the 1546 dtex(1405 denier) yarn per centimeter (inch) of strand used to create thetuftstring. A disc knife cut the yarn immediately after bonding torelease it from the mandrel and create a cut pile, and the pile wasfurther trimmed via a shearing device to a pile height, measured fromthe base of the strand, of 7.9 mm ({fraction (5/16)}th inch). Thisresulted in a tuftstring with a weight of 2.8 grams per linear meter(2.6 grams per linear yard).

The strand used was a sheath/core monofilament, of circular crosssection, 0.71 mm (28 mils) in total diameter. The core was composed ofpolypropylene copolymer in an 80/20 blend of polypropylene (Fina 3868—apolypropylene homopolymer) and grafted polypropylene (POXT1015 anhydridemodified polypropylene that provides increase adhesion to nylon) and thesheath was composed of a copolymer of nylon 6 and nylon 6,6 in a ratioavailable as Capron® 1590 resin from E. I. du Pont de Nemours andCompany. The weight ratio of polypropylene copolymer to nylon copolymerwas 50/50. The outer surface of the strand was uninterrupted; that is,it was a single, cylinder-like, continuous, polymer surface that wasfree of convolutions and crevices typical of a surface comprised of aplurality of small filaments or a plurality of twisted filaments. Suchan uninterrupted surface is suitable for bonding with multifilament pileyarn and subsequently drawing and stretching the strand without breakingthe bond with the pile yarn. The tuftstring was loosely coiled in a drumfor further processing.

A pile construction was then formed by feeding a single tuftstring endthrough a guide and ultrasonically bonding it to a backing mounted on adrum mandrel as shown in FIGS. 6, 7, 8, and 9 using a single ultrasonichorn with a single blade. The second horn shown in FIG. 8 was not usedsince a slow speed was employed.

The backing 90 consisted of three separate layers. One layer, mountedagainst the cylinder, consisted of 0.034 kg/sq m (1 oz per square yard)Sontara® nonwoven, non-bonded web made of spun-laced multifilaments ofnylon 66 staple fibers that have been hydro-entangled. Sontara® nonwovenis available from E. I. du Pont de Nemours and Company. The middle layerwas an extruded sheet of Keldax® 6868 calcium carbonate filledthermoplastic material (also available from E. I. du Pont de Nemours andCompany) 0.64 mm (25 mils) in thickness, like that typically used in theautomotive carpet industry for sound-deadening in automotive floors. Theupper-most layer was a 0.025 mm (1 mil) film of DuPont Bynel* filmformed from DuPont CXA 41E557 maleic anhydride modified polyethyleneresin. The tuftstring was feed through guiding devices and then onto thecylinder where it was ultrasonically bonded to the three layer backingmaterial continuously at 2.0 tuftstrings per centimeter (5 tuftstringsper inch) backing width, using a power setting of 58 watts for theultrasonic tool and at a speed of about 1.8 meters/min (2 yds/min).

Sections of this carpet structure were then further treated by placingthem in a press for one minute under 35,150 kg/sq m (50 psi) pressure,where the platen touching the pile side of the sample was held at roomtemperature while the platen touching the backing side was held at onehundred fifty (150) degrees C. The application of heat and lightpressure caused the nonwoven backing, which was clearly visible on theback surface before pressure treating, to become impregnated by theKedlax® material inner layer and tightly laminate to it. Additionally,the base of the tuftstrings were pressed into the surface of the 0.64 mm(25 mil) Keldax® material layer, causing a slight ribbing effect on thebacking surface opposite the tuftstring, and effectively increasing thecontact area between the tuftstring base and the backing material.Pressing the tuftstrings into the backing is an important step toincrease adhesion of the tuftstring to the backing. It was observedthat, after this treatment, the tuftstrings were very well adhered tothe backing such that it was very difficult to peel off individualtuftstrings from the backing.

Other means of attaching the fabric cover layer to the Keldax® materialsupport layer would be to prelaminate these in a laminating press orbetween rolls before bonding the tuftstrings to the backing substrate.Other means of embedding the tuftstrings into the backing substrate maybe by locally softening the backing substrate and applying sufficienttension to the tuftstring to deform the backing as it is wound onto thebacking substrate on the cylinder.

A scouting test was administered to determine the ability to heat anddeform this carpet structure. It was carried out in the followingmanner. A circular sample, 26.7 cm (10.5 inches) in diameter, of theabove carpet construction was cut and mounted between two pieces of anannular machined aluminum support frame, tightly securing an outer 12.7mm (0.5 inch) ring of the carpet edge using several bolts connecting thetwo annular pieces of the annular support frame. The carpet, securelyheld in the support frame, was then placed, backing side up, in a smalloven approximately 2 cubic feet in volume, set to a temperature of 150C. A thermocouple attached with a small piece of Kapton® adhesive tapeto the center of the sample on the back side was used to monitortemperature. After an oven dwell time of approximately five minutes, thethermocouple temperature read one hundred fifty (150) degrees C. Thecarpet sample, still secured in the annular support ring, was quicklyremoved using insulated gloves and placed on a annular support, mountedin an Instron testing machine, such that the backing faced up. Aplunger, attached to the Instron motion arm, consisting of a 10.2 cm (4inch) diameter polished aluminum hemisphere mounted on a 25.4 mm (1inch) diameter rod, was caused to impinge the carpet sample at a rate of50.8 cm (20 inches) per minute. As the plunger impinged the sample, thesample carpet was deformed, and the load and stroke distance whererecorded. The sample was monitored during stretching visually byobserving the pile side of the carpet. The motion was stopped as soon asdark backing showed clearly between the tuftstring pile rows, or a tearfailure occurred. The deformation distance was recorded at this point asa indication of the maximum ability to mold-shape the carpetconstruction, as is often done for automotive flooring materials.

The above carpet fabrication and testing sequence was repeated for othertuftstring constructions varying the material of composition of thestrand used in the tuftstring. The following strand materials wereevaluated in carpet samples all having the same backing structuredescribed above:

Example 2

Sheath/Core of 50/50 wt. composition; core: Crystar 1995 polyethyleneterephthalate, sheath: Capron® 1590 Nylon 6/66 copolymer. Approximatestrand sheath melting point is one hundred sixty five (165) degrees C.

Example 3

Nylon 6,12 monofilament comprising a copolymer of nylon6,12/Novolac/Capron® 1590 (60/20/20% by weight, respectively). TheNovolac is a poly-phenol polymer additive available from SchenectadyChemical Co. and is useful in this blend to lower the melt temperatureand improve adhesion of nylon 6,12 in the strand to the nylon 6,6 pileyarn. Approximate strand melting point is two hundred fifteen (215)degrees C.

Example 4

Nylon 6 monofilament. Approximate strand melting point is two hundredtwenty three (223) degrees C.

Example 5

3410 dtex total (3100 total denier) sheath/core staple wrapped strandmade on a DREF machine; Core: continuous glass multifilament core—1595dtex (1450 denier); sheath: 2.0 dtex/f (1.8 dpf), 38.1 mm (1.5 inch)staple length fiber comprising a copolymer of nylon 66/MPMD (70/30% byweight respectively). Approximate strand sheath melting point is onehundred fifty (150) degrees C.

Example 6

Tufted Control: 0.47 kg/sq m (14 oz/sq yd) pile yarn comprising 3.2 mm({fraction (1/8)} inch) gage tufted 1546 dtex (1405 denier) singles BCF,7.9 mm ({fraction (5/16)}th inch) pile height; woven slit polypropyleneprimary backing, ELVAX resin binder adhesive precoat and 0.64 mm (25mil) Keldax® 6868 sound barrier laminated together. The table belowshows the failure limits recorded and maximum force of deformation.Deformation Max. Force Carpet Sample (Strand) (cm) (Inch) (N) (Lbs) Ex.6) Tufted Control 10.2 (4.0) 2113 (475) Ex. 1) Polypropylene/Nylon 9.5(3.75) 445 (100) Ex. 3) Nylon 6,12 8.9 (3.50) 667 (150) Ex. 4) Nylon 66.4 (2.50) 1112 (250) Ex. 2) Polyester/Nylon 5.5 (2.15) 445 (100) Ex. 5)Nylon/Glass 3.2 (1.25) 222  (50)

The measure of success for formability of carpets in automotiveapplications can be different for various carpet applications. However,it is expected that carpet material which can be deformed at least 7.6cm (3.0 inches) will be useful for a variety of automotive shaped carpetapplications. Looking at the samples which failed at a deformation ofless than 7.6 cm (3.0 inches), samples 4 and 2 had strands with meltingpoints which are quite a bit higher than the molding temperature of theKeldax® polymer (150 degrees C.), so they provided significantresistance to deformation so failure occurred at a low force and lowdeformation. Sample 5 had a strand with a core of continuous glassfilaments which also resisted deformation at one hundred fifty (150)degrees C., although the sheath had a melt point at the sametemperature. Samples 1 and 3 had strand melting points close enough toone hundred fifty (150) degrees C. to deform easily at the one hundredfifty (150) degrees C. test temperature. Therefore, it is anticipatedthat thermoplastic strand constructions having a melting point less thanabout two hundred twenty (220) degrees C. will be compatible for moldingconstruction described above involving combinations of Keldax® 6868sound deadening material normally processed at approximately one hundredfifty (150) degrees C. in the industry. Based on the above scoutingtest, it appears that the polypropylene/nylon sheath/core strand ofsample 1, and the nylon 6,12 monofilament strand of sample 3 would begood strand candidates for a moldable tuftstring carpet.

This test is not relevant for tuftstring mats which do not get stretchedand molded. In this case, it is anticipated that strands in samples 1,2, 3, 4, and 5 would be acceptable candidates.

The strands for the sample tuftstrings were also drawn to failure on anInstron machine to examine their expected draw force performance. Loadat 15% Modulus Break load Elongation elongation Sample kg/sq m (PSI)newtons (Lbs) % newtons (lbs) 1  62,600  (89) 19.6 (4.4) 321 1.25 (0.28) 3  67,500  (96) 33.4 (7.5) 112 5.8 (1.3) 4 308,600 (439) 124.5(28)   186 13.8 (3.1) 2  48,500  (69)* 115.6 (26)   326 9.3 (2.1) 5428,900 (610) 36.9 (8.3) 2.3 broke > (10)   44.5 N6, 6 337,500 (480)151.2 (34)   227 13.8 (3.1)*this value is an anomaly and is not considered validThe N6, 6 stand was a reference point representing the strand suggestedin U.S. Pat. No. 5,547,732 (Edwards et al.).

The carpet samples that performed well, samples 1 and 3, used strandsthat had low modulus and low load of 8.9 newtons (2.0 lbs.) or less at15% elongation which is the maximum for a tuftstring at the 7.6 cm (3.0inch) ram deflection considered acceptable performance for a moldabletuftstring carpet. As a screening test, it is believed this is anacceptable way to identify good strand candidates for moldabletuftstring carpets.

Example 7 Tuftstring for an Automotive Mat Construction ContainingBristles

A tuftstring suitable for fabrication of automotive mats containing ablend of two pile fiber types of widely variant dtex (denier) wasfabricated. One of the pile fibers was 1546 dtex total (1405 totaldenier), 19.4 dtex/f (17.6 dpf), producer colors bulked continuousfilament automotive carpet-yarn, while the second pile fiber was 743dtex (675 denier) monofilament nylon fiber.

A tuftstring was formed in the following manner. Two multifilament feedstrands of 1546 dtex total (1405 total denier), 19.4 dtex/f (17.6 dpf),yarn and two feeds of 743 dtex (675 denier) nylon 66 monofil were fedfrom a creel and brought together without added twist (over end takeoffintroduces a very low level of twist) in an eyelet and further feed tothe wrapping mechanism for a triangular mandrel tuftstring module ofFIG. 6. The grouped pile yarns were wrapped on a triangular mandrel suchthat there were approximately 8.7 (22) single wraps per centimeter(inch) each of 1546 dtex (1405 denier) BCF yarn and 8.7 (22) singlewraps per centimeter (inch) of monofilament pile fiber. The tuftstringwas formed at 1.8 meters (2 yards) per minute. The pile fibers werebonded to the strand using an ultrasonic tool as described in Example 1,set to a power of 44 watts. The pile fiber was cut with a rotating discknife to free it from the mandrel and form a cut pile, and furthertrimmed to a pile height of 7.9 mm ({fraction (5/16)}th inch) at ashearing station.

The strand material to which the two pile fiber components were bondedwas a 3410 total dtex (3100 total denier) strand composed of acontinuous glass multifilament core of 1595 dtex (1450 denier), and astaple fiber sheath of 1815 dtex total (1650 total denier). The sheathfiber was 2.0 dtex per filament (1.8 dpf), 38.1 mm (1.5 inch) cutlength, nylon copolymer fiber which was wrapped onto the continuousglass fiber using the Dreft textile process to form the sheath aroundthe glass fibers. The nylon copolymer composition was 70/30 nylon 66 andMPMD. It was observed that both the 1595 dtex (1405 denier) 19.4 dtex/f(17.6 dpf) pile fiber, and the heavy 743 dtex (675 denier) monofilbonded to this strand material securely such that this tuftstring couldbe collected for further processing. FIG. 22 shows the tuftstring formedin the above manner arranged in closely spaced rows and attached to abacking substrate similar to that described referring to FIG. 3. It canbe usefully employed as automotive and industrial carpets and mats whichhave the combined features of excellent automotive carpet aesthetics, anovel dirt removal feature for cleaning occupant's shoes, and improvedwear resistance provided by the bristles.

Example 8 Automotive/Floor Mat Construction Using Tuftstrings

A carpet mat structure was fabricated in the following manner: first, atuftstring was fabricated on a triangular mandrel similar to that shownin FIGS. 5 and 6. The tuftstring was formed at 1.8 meters (2 yards) perminute by wrapping two strands of 1546 dtex total (1405 total denier),producer colored, bulked continuous multifilament nylon 6,6 yarn,produced commercially by E. I. du Pont de Nemours and Company, aroundthe mandrel. A staple wrapped sheath/core strand was used for thetuftstring strand. The ultrasonic power used to bond the pile yarn tothe strand was about 30 watts and the ultrasonic tool load on a 19 mm({fraction (3/4)} inch) long tool was approximately 10,500 kg/sq m (0.15psi). There were about 10.2 (26) single wraps of the 1546 dtex (1405denier) yarn per centimeter (inch) of strand used to create thetuftstring. A disc knife cut the yarn immediately after bonding torelease it from the mandrel and create a cut pile, and, in the case ofthe triangular mandrel, the pile was further trimmed via a shearingdevice to a pile height, measured from the base of the strand, of about3.2 mm ({fraction (1/8)}th inch). This resulted in a tuftstring with aweight of about 2.8 grams per linear meter (2.6 grams per linear yard).

The strand used was a 3410 dtex total (3100 total denier) sheath/corestaple wrapped strand made on a DREF machine; Core: continuous glassmultifilament core—1595 dtex (1450 denier); sheath: 2.0 dtex/f (1.8dpf), 38.1 mm (1.5 inch) staple length fiber comprising a copolymer ofnylon 66/MPMD (70/30% by weight respectively). Approximate strand sheathmelting point is one hundred fifty (150) degrees C. The tuftstring wasloosely coiled in a drum for further processing.

A pile construction was then formed by feeding a single tuftstring endthrough a guide and ultrasonically bonding it to a backing mounted on acylinder as shown in FIGS. 6, 7, 8, and 9 using a single ultrasonic hornwith a single blade. The second horn shown in FIG. 8 was not used sincea slow speed was employed.

The backing 90 consisted of a single layer of uncured styrene butadienerubber about 2.54 mm (100 mils) thick. It was mounted against thecylinder 82 which is covered with a release film. The tuftstring wasfeed through guiding devices and then onto the cylinder where it wasultrasonically bonded to the backing material continuously at 2.8tuftstrings per centimeter (7 tuftstrings per inch) backing width, usinga power setting of about 58 watts for the ultrasonic tool, a pressure onthe tool of about 22.2 newtons (5 pounds), and at a speed of about 1.8meters/min (2 yds/min). The force on the horn and the power used areonly that necessary to temporarily tack the tuftstring to the backing 90for further handling. It should be sufficient power and pressure toembed the tuftstring into the surface of the backing by about 0.13-0.76mm (5-30 mils), however. It should be low enough in pressure and energyso the ultrasonic horn does not deform and weaken the backing under thetuftstring. The tuftstring and backing assembly thus formed represents acarpet mat preform that can be handled and shipped to a moldingoperation without damage.

Sections of this carpet structure (about 30.5×40.6 cm (12×16 inches)were then further treated by placing them on a mold plate in a pressexerting about 9000-44,500 newtons (2000-10,000 pounds) force for about20 minutes which produced about 7,030-35,150 kg/sq m (10-50 psi)pressure on the sample. The platen touching the pile side of the samplewas held at room temperature, while the platen touching the moldsupporting the backing side was held at one hundred seventy (170)degrees C. In this sample a pressure of 7,030 kg/sq m (10 psi) was usedto achieve the necessary pressure for molding the nibs without usingexcess pressure that would crush the carpet pile yarn. By pre-embeddingthe tuftstring in the backing, a high pressure is not needed to ensuregood empregnation of the SBR into the pile yarn of the tuftstring. Themold plate was an aluminum plate having holes for forming a plurality ofspaced nibs on the bottom of the mat. A reinforced Teflon-coated sheetwas placed between the mold plate and platen to prevent the SBR frominadvertently contacting the hot platen. The application of pressureheld the assembly flat as it was heated and the combination with heataided in further impregnating the tuftstrings into the backing,extruding nibs on the bottom side of the backing, and curing the SBRmaterial. The molding time exceeding about 2 minutes is needed just tocure the SBR backing. After molding, the sample was removed from thepress, placed carpet pile side down, and allowed to cool. The base ofthe tuftstrings were pressed into the surface of the 2.54 mm (100 mil)SBR backing by about 0.58 mm (23 mils) which is important for increasingthe contact area between the tuftstring base, comprising the pile yarn,and the backing material. Embedding the tuftstrings into the backing isan important step to increase adhesion of the tuftstring to the backing.It was observed that, after this treatment, the tuftstrings were verywell adhered to the backing such that it was very difficult to peel offindividual tuftstrings from the backing. By pre-embedding thetuftstrings into the backing during the bonding step prior toapplication of heat and pressure in the press, a lower pressure in thepress can be used to cure the SBR, and less crushing of the pile yarn isevident.

To test the durability of the sample, it was placed in a Vetterman Drumtester and subjected to 20,000 cycles. No separation of the tuftstringsfrom the backing was observed. Another duplicate sample was also placedin a Swivel Caster tester and subjected to 20,000 cycles. No separationof the tuftstrings from the backing was observed.

Example 9 Mat Preform Made by Embedding Tuftstring into a Tacky RubberBacking Without Ultrasonics

A carpet mat preform suitable for molding into a finished mat wasconstructed in the following manner: First, tuftstring was formed on asquare mandrel (as in a tuftstring forming module as in FIG. 10) at 9.1m/min (10 ypm) from Nylon BCF 1546 dtex (1405 denier) yarn attached to asheath/core strand comprising nylon staple sheath and a glass core; madeon a DREF machine.

The yarn feed was two ends of 1546 dtex (1405 denier) BCF singlesproducer colored yarn manufactured by E. I. DuPont de Nemours andCompany having a total dtex of 3091 (denier of 2810). The DREF strandwas composed of glass multi-filament core of 1546 dtex (1450 denier)continuous glass fiber and a staple fiber sheath of 3.3 dtex/f (3.0 dpf)nylon 66/MPMD copolymer where the total sheath dtex was 1815 (denier was1650) and the individual filaments were 3.3 dtex/f (3 dpf) and 45 mm(1.77 inch) cut length. The total dtex (denier) of the DREF strand was3410 (3100).

The tuftstring was formed as described in the body of the patent on asquare mandrel and cut to 6.4 mm ({fraction (1/4)} inch) pile height ontwo opposite corners by shifting the cutters off center to create twotuftstrings with each having a total weight of 1.9 grams per meter (1.7grams per yard). The two tuftstrings from the remaining corners had along pile height not suitable for this test and they were discarded. Itwas observed that the pile on the tuftstring was deployed in twocontinuos rows and that the strand showed clearly between the rowsunobstructed by cross-over filaments. The filaments of each row weredeployed at an angle of between ten (10) degrees and eighty (80) degreesfrom the base plane of the strand and formed two well defined looselyentangled rows.

A preform for a molded rubber backed mat was formed in the followingmanner: A 1.52 mm (60 mil) thick un-cured SBR rubber sheet having acomposition of approximately 60% clay filler, 5% carbon black, 10%napthalenic oil, and 25% SBR rubber was mounted on a steel cylinder 91cm (36 inches) in circumference and 91 cm (36 inches) in length similarto the cylinder 82 of FIG. 6. Double sided adhesive tape was used tosecure the uncured rubber to the roll at the edges and at intervalsalong the sheet.

Tuftstring from the above bonding process was piddled into a can andstored overnight for use the next day. The end of this tuftstring wasthen threaded through some simple z-path guides to create a small amountof back tension and then under a blade guide which pressed against thestrand. The blade guide was 2.54 mm (100 mils) thick at its base with aguide groove at its base 0.64 mm (25 mils) in radius centered on thebase of the blade and 0.64 mm (25 mils) in depth. The blade was 25.4 mm(1 inch) in length with a 25.4 mm (1 inch) radius curvature at the entryedge. The guide blade was centered on the strand such that as thetuftstring passed under the guide, the base of the tuftstring was forcedto embed into the rubber. The rubber was 1.52 mm (60 mils) thick. Theembedding guide was fixed at a 1.27 mm (50 mil) distance from thecylinder surface to achieve a 0.25 mm (10 mil) initial embedding of thetuftstring base into the rubber. It was observed that the tuftstringembedded in this manner into the rubber would stick sufficiently to therubber to allow continuous winding of parallel rows of tuftstring ontothe rubber at a gauge of 8 tuftstrings per inch. It was also observedthat the indenting of the tuftstring into the rubber caused the outerpile row to rotate upright somewhat thereby decreasing the space betweenthe rows on the tuftstring. This enabled a deflection guide toefficiently further upright the pile row, just prior to laydown of thenext row by the blade guide, creating uniform rows of uprighted pile.The full surface of the rubber mat was laid-on with a pile surface inthis manner. Further, after completing the tuftstring winding, the pilesurface was sprayed with a mist of water and a heat gun was used to heatthe pile surface evaporating the water, further enhancing the bulk ofthe pile fiber and substantially eliminate the space between rows. Thiswas observed to create a uniform pile surface material. The pile surfacewas cut at one point across the length of the cylinder and the rubbersheet and pile surface was removed from the cylinder. It was observedthat the attachment of the tuftstrings to the rubber remained intact onremoval from the cylinder and the this rubber and pile surface preformcould be transported in the normal manner to a platen press. FIG. 23shows a preform as described having tuftstings 41 attached to an uncuredrubber backing 582.

Nine hundred twenty nine square centimeters (one square foot) of thispile covered, uncured, rubber backing was placed between the platens ofa hydraulic press where the bottom platen was heated to 160 C andcontained a pattern of 2.5 mm (0.1 inch) diameter nib holes on 25.4 mm(1 inch) centers. The top platen was held at room temperature. Apressure of 352,000 kg/sq m (500 psi) was applied to the rubber and pilearticle for twenty minutes after which the platens were opened and themat article removed. It was observed that the tuftstrings were welladhered to the rubber and that no bleed-through of rubber occurred intothe pile surface.

FIG. 23 is also representative of a cured carpet mat (584) as justdescribed with nibs 586 (shown dashed) molded into the bottom surface ofthe now cured backing (588). FIG. 23 is also representative of theultrasonically joined tuftstrings and rubber backing assembled preformand finished mat of Example 8.

FIG. 24 shows a variation of the carpet mat preform/finished carpet ofExample 9 as illustrated in FIG. 23. The preform/finished mat 590 hasreinforcing strands 592 inserted perpendicular to the tuftstrings 41.These reinforcing strands 592 may be made from the same material as thetuftstring strands 45. These are added to the tacky surface of thebacking before the tuftstrings are pressed into place. The reinforcingstrands add to the strength of the backing in the directionperpendicular to the tuftstrings to balance the load carrying strengthof the finished mat which has the tuftstring strands carrying the loadin the tuftstring direction.

FIG. 25 shows another variation of a carpet mat that is not intended tobe drawn in a molding operation. It comprises tuftstrings 41 assembledto a backing substrate 594 comprising a composite of Keldax® 596 and aBynel® adhesive layer 598. The tuftstring strand is preferably asheath/core structure and includes a core of fiberglass multifilaments.It would be made by mounting the composite backing to cylinder 82 ofFIG. 6 and ultrasonically attaching the tuftstrings to the adhesivesurface of the backing to produce the preform shown in the FIG. 25. Thepreform would then be place briefly in a press similar to that describedin Example 8 for a brief time since the Keldax does not require curingas does rubber. The heat and pressure of the press softens the adhesiveBynel layer and further embeds the tuftstrings into the backingsubstrate which improves the attachment strength between the tuftstringand backing.

FIG. 26 shows another variation of a carpet mat that is not intended tobe drawn in a molding operation. It comprises tuftstrings 41 attachedfirst to a backing substrate comprising a thermoplastic sheet material600, which may also include reinforcing fibers and an adhesive filmfacing the tuftstrings 41. The tuftstring strand 45 is preferably asheath/core structure with a fiberglass core 602. This sheet material600 may comprise conventional tufted carpet primary backing materials ormay comprise a special tuftstring carpet backing material described inU.S. Pat. No. 5,470,648 (Pearlman), incorporated herein by reference.The backing of the Pearlman patent comprises a composite structure of alayer of non-bonded, non-woven nylon sheet adhesively attached to thetop and bottom of a fiberglass scrim. This subassembly of tuftstringsand sheet material is then laminated to a sub-backing 604 of a Keldax®layer 606 covered with an adhesive layer 609 of Bynel®. The carpetassembly is placed in a platen press and heated until the assembly issecurely united. This produces a mat that is unusually strong andstable, but at an increased cost over those mats of FIGS. 23, 24, and25.

FIG. 27 shows a close-up portion of a wound package 552 of tuftstring.Surprisingly the tuftstring 41 can be guided and layed down on a packagesurface 558 with a conventional yarn winder, such as made by Leesona,without twisting or damaging the pile yarn. The tuftstring can also bebackwound off the package and used to make a carpet with goodappearance. This is possible by winding under low tension (about 100grams) and at a low helix angle 554 measured off a reference line 556perpendicular to the package winding axis. Preferably, the helix angle556 is plus or minus ten to thirty (+/−10-30) degrees. The monolithicpile structure provides torsional stability to resist twisting and itkeeps the filaments together at the crossovers and during backwinding.The Figure shows the tuftstring wound on with the strand 45 facingoutward and the base region of the tuftstring facing inward. Asubstantial portion of the filaments in the rows 616 and 618 areoriented substantially parallel to the package surface 558 so the strandremains accessible. A conventional traverse and guide are used to guidethe tuftstring on the package. The tuftstring can also be wound onto thepackage with the strand facing inward and the base region of thetuftstring facing outward. In this orientation a larger portion of thefilaments of each row are oriented substantially parallel to the packagesurface since the strand tension tends to flatten the pile rows.

FIG. 28 shows a unique tuftstring structure of the invention. It is acarpet structure 560 where the tuftstrings 41 and 41 a are arranged atzero and ninety degrees respectively on a backing substrate. Thisresults in a “waffle” pattern of pile yarn on the carpet and the patternhas a three dimensional surface with wells 562 and valleys 564 betweenridges 566 of pile yarn. The structure is made on the carpet formingmodule 73 in FIG. 6 by first placing a backing substrate on the cylinder82 and then spirally winding and ultrasonically bonding a firsttuftstring at a wide pitch of about 12.7 mm ({fraction (1/2)} inch) tothe backing. The backing is then cut off the cylinder and reoriented sothe tuftstrings are arranged along the axis of cylinder 82. A secondtuftstring is then spirally wound at a pitch of 12.7 mm ({fraction(1/2)} inch) over the first tuftstring and ultrasonically bonded to thebacking and to the first tuftstring where the two cross. This samepattern can also be made by spirally winding a single tuftstring at ahelix angle of about 45 degrees back and forth along the cylinder 82 andbuilding up the tuftstring coverage until there is a tuftstring every12.7 mm ({fraction (1/2)} inch) in both helix directions. In this waythe bias of the pattern is aligned with the cylinder axis. The helixangle may be changed plus or minus twenty (+/−20) degrees to makepatterns where the tuftstrings are at angles different than zero andninety degrees. In general, a pile article can be arranged as aplurality of intersecting rows of tuftstrings to form a pile surfacestructure, by attaching them to a backing substrate in the followingmanner:

-   -   A first group of tuftstrings are arranged in first parallel rows        spaced apart at a pitch of less than 1.6 tuftstrings per        centimeter (four tuftstrings per inch) and attached to the        backing substrate, the yarns at the point of attachment to the        strand being attached to the backing substrate and the pile        forming filaments arranged to create a pile surface spaced from        the backing substrate;    -   A second group of tuftstrings are arranged in second parallel        rows crossing said first parallel rows at a pitch of less than        1.6 tuftstrings per centimeter (four tuftstrings per inch), and        attached to the backing substrate and to the first group of        tuftstrings arranged in the first parallel rows, the yarns at        the point of attachment to the strand being attached to the        backing substrate and the pile forming filaments arranged to        create a pile surface spaced from the backing substrate,    -   whereby a waffle pattern is produced at the pile surface by a        plurality of wells formed adjacent the intersections between the        first and second parallel rows. The pitch may vary depending on        the bulk and length of the pile yarn on the tuftstring so the        pile substantially covers the backing substrate. About 0.3        tuftstrings per centimeter (0.75 tuftstrings per inch) is a        practical minimum pitch for conventional automotive pile.

In FIG. 28 the tuftstring strands for tuftstrings 41 in the zero degreedirection appear as dark lines as do the tuftstring strands fortuftstrings 41 a in the ninety degree direction. These are the valleyregions 564 in the third dimension. The wells 562 in the third dimensionare where the tuftstring strands for tuftstrings 41 and 41 a cross andthese appear as dark spots. The lighter regions of the pattern are wherethe pile yarns from adjacent tuftstrings blend together as in the row116 (not discernable) of one tuftstring blends with row 118 (notdiscernable) of the adjacent tuftstring. Such a three dimensional carpetstructure, in addition to presenting, an interesting pattern, may alsofunction to capture and hide dirt in the well regions or channel awayliquids in the valley regions.

There is sometimes a problem when making carpet mats on a backingsubstrate of uncured rubber, that the uncured rubber is too elastic andcannot be held securely on the cylinder 82 with tape applied only at theedges. When pressure is applied to embed the tuftstring into thebacking, the backing stretches and a ripple forms behind the guide tool(unergized ultrasonic horn). This problem can be solved in several ways.One way is to apply a two-sided sticky tape to substantially cover thesurface of the cylinder and apply the backing to the tape. This presentsproblems getting the assembled carpet cleanly off the cylinder and thetape must be replaced often. Another way is to provide a cylinder with aporous surface and apply a vacuum to the porous surface. The backingwould be applied to the porous surface and be held securely by thevacuum. This would work well but it would be costly to fabricate thecylinder and continuously operate a vacuum source.

A third solution is discussed referring to FIG. 21 which comprisesplacing the uncured rubber backing 568 on the cylinder 82 and thenwrapping a retaining cord 570 spirally over the surface of the backing.The cord 570 would be wrapped in a first rotational direction 572 and ata pitch that is the same as the desired tuftstring pitch. The tuftstring41 would then be spirally wrapped over the backing 568 in a secondrotational direction 574 opposite the direction of the retaining cord.As the tuftstring 41 is wrapped on the backing 568 in direction 576, theretaining cord 570 is unwrapped from the backing 568 in direction 578just in advance of the tuftstring 41 so the cord 570 does not interferewith the placement of the tuftstring. The cord 570′ still remaining onthe backing is close enough to the placement position of the tuftstringso the backing is still held securely and no rippling or stretching ofthe backing occurs.

The tuftstring may be placed on a path on the backing which is spacedfrom the path of the retaining cord, or it may follow the path of theretaining cord. The retaining cord may not need to be layed onto thebacking in a precise path as long as the pitch is the same as that ofthe tuftstring. If the retaining cord is layed down precisely, thetuftstring may be spaced from the retaining cord and the retaining cordleft in place on the backing until all the tuftstring is bonded to thebacking. The retaining cord may then be removed from between thetuftstrings, or the cord left in place held by the tacky uncured rubbersurface. If left in place, it may help reinforce the backing. If it isdesired to reinforce the backing in a direction at an angle to thetuftstring, the retaining strand may be wound in a spiral array thatcrossed that of the tuftstring, and the tuftstring would be bondedacross the retaining strand.

In accordance with the present invention:

-   -   the filaments of the pile article are bonded to the support        strand by fusion of the thermoplastic polymer of the support        strand and the filaments (2);    -   the strand surface and said filaments are of the same        thermoplastic polymer family (3)    -   the surface of said strand and said filaments are selected from        the group of nylon, polyester, and polypropylene polymer (4);    -   the strand comprises a core of continuous glass filaments and at        least one multifilament staple yarn wrapped at least partially        around said core (5);    -   the strand comprises a support strand having an uninterrupted        outer surface, the strand permanently drawable free of fracture        up to 15% at a draw temperature of 150 degrees C. and a draw        force of 9.0 newtons (2 pounds) or less at said draw        temperature, to thereby limit the draw force required to draw        the pile article (6);    -   the pile article is arranged in a wound package comprising an        overlapping, reversing helical array where the helix angle is        between plus or minus 10-30 degrees and where the strand is        either facing outwardly and the base region of the filaments is        facing inwardly (7) or wherein the strand is facing inwardly and        the base region of the filaments is facing outwardly (8) and a        substantial portion of the filaments on the two rows of the pile        article extend outward in opposed directions from the strand        substantially parallel to the package surface and with the        strand facing outward throughout the package;    -   the pile article arranged as a preform for a pile surface mat,        the pile article being arranged in closely spaced rows of 6-10        pile articles per inch, and attached directly to a tacky uncured        rubber sheet having a thickness of 0.8-5.0 mm (30-200 mils).,        where the base region of said pile articles is embedded into the        rubber sheet to a depth of 0.13-0.64 mm (5-25 mils) (10).    -   the pile article wherein the thermoformable sheet is a calcium        carbonate filled thermoplastic material and the adhesive film is        a polyethylene resin (12);    -   the pile article carpet wherein the thermoformable sheet is a        calcium carbonate filled thermoplastic material and the adhesive        film is a polyethylene resin, and the fabric is a nonwoven        nonbonded web of spun-laced multifilaments. (14)    -   the pile article of claim 15 having a backing substrate attached        to the yarn of the pile articles at the point of attachment of        the yarn to the strand and opposite the pile surface. (16)    -   the pile surface structure wherein said adhesive surface        comprises spaced apart adhesive ribbons aligned with the base        surface of each of said elongated pile articles. (18)    -   a method wherein said applying step comprises:        -   urging an ultrasonic horn against said pile article, and the            method further comprising the step of:        -   applying ultrasonic energy to the horn to heat the interface            between said pile article and said backing. (22)

1. An automotive pile surface structure, comprising: a backing substratecomprising a thermoplastic sound absorbing sheet having a density of atleast 1.0 g/cc and a thickness of at least 0.4 mm (15 mils); an adhesivesurface on one surface of said substrate; a fabric stabilizing layer onthe surface of said backing opposing said adhesive surface; a pluralityof pile articles, each comprising a support strand having bonded theretoa pile yarn comprising filaments of thermoplastic polymer, said yarnhaving a dense portion of filaments bonded together and secured to thesurface of the support strand at a base by fusion of the thermoplasticpolymer of the support strand and the filaments; the pile articlesplaced one next to the other and said base bonded to the adhesivesurface of said backing substrate with the tufts extending away from thebacking; said base surface of the elongated pile article embedded belowthe adhesive surface of said backing substrate so that said adhesivesurface engages pile yarns beyond said base surface.
 2. The pile surfacestructure of claim 1 wherein said adhesive surface comprises spacedapart adhesive ribbons aligned with the base surface of each of saidelongated pile articles.
 3. In a tuftstring carpet assembly comprising abacking substrate and a pile article attached thereto, with each pilearticle comprising a support strand having attached thereto a pluralityof pile forming yarns comprising multifilaments, the yarns at the pointof attachment to the strand being attached to the backing substrate andthe pile forming filaments arranged to create a pile surface spaced fromthe backing substrate, the improvement comprising: a monofilament yarnblended with the multifilament yarn and attached to said support strandto create stiff bristle filaments distributed in the pile surface.
 4. Amethod of forming a pile surface article preform, comprising the stepsof: a) arranging a pile article to substantially cover a backingsubstrate, said pile article comprising a strand having attached theretoopposed rows of loosely entangled pile filaments, the rows spaced apartmaking the strand accessible and the rows connected to each other and tothe strand at a base; b) applying pressure to said strand between saidrows to press said pile article against said backing substrate, and c)embedding the base of said pile article into said backing and causingsaid rows to rotate toward one another to reduce said space between therows on the pile article.
 5. The method of claim 204, further comprisingthe step of: d) applying heat to said pile filaments thereby bulkingsaid filaments and substantially eliminating said space between rows. 6.The method of claim 4 wherein said applying step b) comprises: urging anultrasonic horn against said pile article, and the method furthercomprising the step of: applying ultrasonic energy to the horn to heatthe interface between said pile article and said backing.
 7. A method offorming a pile surface article preform, comprising the steps of: a)holding a backing substrate on a cylindrical drum by applying a vacuumto the side of the backing contacting said drum; b) winding a pilearticle, comprising a strand and pile yarn attached at a base region ofthe pile article, spirally over the surface of the backing substrate sothe pile yarn of the pile article substantially covers the backingsubstrate and; c) pressing the pile article strand against the backingsubstrate to embed the pile article base region in the backing to adepth of 0.13-0.64 mm (5-25 mils).
 8. In a method of forming a pilearticle by guiding support strands along guiding grooves on ridgespositioned at the corners of a multi-sided mandrel, wrapping a pile yarnaround the mandrel over the ridges and the strands guided thereon toform loops of yarn, transporting the loops and strands under a bondingmeans aligned with the support strands and bonding the yarn to thestrands, the improvement comprising the steps of: a) providingadditional guiding grooves on each side of the mandrel between theridges on the mandrel and guiding additional support strands in theadditional grooves; b) bonding the yarn to the strands guided at thecorners of the mandrel so that the corner strands positively transportthe yarn attached thereto; c) bonding the yarn to the strands guided onthe sides of the mandrel after said bonding at the corners to attach theadditional strands to the yarn; and d) cutting said loop of yarn betweenthe support strands to form a plurality of pile articles and forwardingthe pile articles off the mandrel.